2021/06/24 更新

写真a

オオカワ マサシ
大河 正志
OHKAWA Masashi
所属
教育研究院 自然科学系 情報電子工学系列 教授
自然科学研究科 電気情報工学専攻 教授
工学部 工学科 教授
職名
教授
外部リンク

学位

  • 工学博士 ( 1989年3月   大阪大学 )

研究分野

  • ものづくり技術(機械・電気電子・化学工学) / 電子デバイス、電子機器

経歴

  • 新潟大学   工学部 工学科   教授

    2017年4月 - 現在

  • 新潟大学   自然科学研究科 電気情報工学専攻   教授

    2010年4月 - 現在

  • 新潟大学   自然科学研究科 電気情報工学専攻   教授

    2010年4月 - 現在

  • 新潟大学   福祉人間工学科   教授

    2004年4月 - 2017年3月

  • 新潟大学   工学部   講師

    1993年4月 - 1995年5月

  • 新潟大学   工学部   助手

    1989年4月 - 1993年3月

▶ 全件表示

 

論文

  • Physical-random number generation via a diode laser's frequency noise: an investigation into frequency discriminator 査読

    Arai Hideaki, Sato Takashi, Doi Kohei, Ohdaira Yasuo, Sakamoto Shuichi, Ohkawa Masashi

    JAPANESE JOURNAL OF APPLIED PHYSICS58 ( 1 )   2019年1月

  • Space gravitational-wave antennas DECIGO and B-DECIGO

    Seiji Kawamura, Takashi Nakamura, Masaki Ando, Naoki Seto, Tomotada Akutsu, Ikkoh Funaki, Kunihito Ioka, Nobuyuki Kanda, Isao Kawano, Mitsuru Musha, Kazuhiro Nakazawa, Shuichi Sato, Takeshi Takashima, Takahiro Tanaka, Kimio Tsubono, Jun’ichi Yokoyama, Kazuhiro Agatsuma, Koh suke Aoyanagi, Koji Arai, Akito Araya, Naoki Aritomi, Hideki Asada, Yoichi Aso, Dan Chen, Takeshi Chiba, Toshikazu Ebisuzaki, Satoshi Eguchi, Yumiko Ejiri, Motohiro Enoki, Yoshiharu Eriguchi, Masa Katsu Fujimoto, Ryuichi Fujita, Mitsuhiro Fukushima, Toshifumi Futamase, Rina Gondo, Tomohiro Harada, Tatsuaki Hashimoto, Kazuhiro Hayama, Wataru Hikida, Yoshiaki Himemoto, Hisashi Hirabayashi, Takashi Hiramatsu, Feng Lei Hong, Hideyuki Horisawa, Mizuhiko Hosokawa, Kiyotomo Ichiki, Takeshi Ikegami, Kaiki T. Inoue, Hideki Ishihara, Takehiko Ishikawa, Hideharu Ishizaki, Hiroyuki Ito, Yousuke Itoh, Kiwamu Izumi, Shinya Kanemura, Nobuki Kawashima, Fumiko Kawazoe, Naoko Kishimoto, Kenta Kiuchi, Shiho Kobayashi, Kazunori Kohri, Hiroyuki Koizumi, Yasufumi Kojima, Keiko Kokeyama, Wataru Kokuyama, Kei Kotake, Yoshihide Kozai, Hiroo Kunimori, Hitoshi Kuninaka, Kazuaki Kuroda, Sachiko Kuroyanagi, Kei ichi Maeda, Hideo Matsuhara, Nobuyuki Matsumoto, Yuta Michimura, Osamu Miyakawa, Umpei Miyamoto, Shinji Miyoki, Mutsuko Y. Morimoto, Toshiyuki Morisawa, Shigenori Moriwaki, Shinji Mukohyama, Shigeo Nagano, Kouji Nakamura, Hiroyuki Nakano, Kenichi Nakao, Shinichi Nakasuka, Yoshinori Nakayama, Erina Nishida, Atsushi Nishizawa, Yoshito Niwa, Taiga Noumi, Yoshiyuki Obuchi, Naoko Ohishi, Masashi Ohkawa, Kenshi Okada, Norio Okada, Koki Okutomi, Kenichi Oohara, Norichika Sago

    International Journal of Modern Physics D   2018年6月

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    © 2018 World Scientific Publishing Company DECi-hertz Interferometer Gravitational-wave Observatory (DECIGO) is a future Japanese space gravitational-wave antenna. The most important objective of DECIGO, among various sciences to be aimed at, is to detect gravitational waves coming from the inflation of the universe. DECIGO consists of four clusters of spacecraft, and each cluster consists of three spacecraft with three Fabry–Perot Michelson interferometers. As a pathfinder mission of DECIGO, B-DECIGO will be launched, hopefully in the 2020s, to demonstrate technologies necessary for DECIGO as well as to lead to fruitful multimessenger astronomy. B-DECIGO is a small-scale or simpler version of DECIGO with the sensitivity slightly worse than that of DECIGO, yet good enough to provide frequent detection of gravitational waves.

    DOI: 10.1142/S0218271818450013

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  • Output characteristics for high-order resonance modes in resonance-type guided-wave optical acoustic emission sensors 査読

    Kenta Shimizu, Masashi Ohkawa, Takashi Sato

    22nd Microoptics Conference, MOC 20172017-   238 - 239   2018年1月

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:Institute of Electrical and Electronics Engineers Inc.  

    A resonance-type guided-wave optical acoustic emission (AE) sensor consists of a diaphragm and a single-mode optical waveguide. In order to increase detectable frequency, the feasibility of application of high-order resonance modes was examined by their measured output characteristics using acoustic pulses or continuous waves instead of AE pulses.

    DOI: 10.23919/MOC.2017.8244574

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  • Diaphragm thickness-dependent sensitivity in a glass-based guided-wave optical microphone 査読

    Yutaro Karasawa, Masashi Ohkawa, Takashi Sato

    22nd Microoptics Conference, MOC 20172017-   248 - 249   2018年1月

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:Institute of Electrical and Electronics Engineers Inc.  

    Our original guided-wave optical microphone consists of a diaphragm and a single-mode optical waveguide. Sensitivity is an important specification for microphones, and is theoretically known to be dependent on diaphragm thickness. In this study, we fabricated three microphones with different diaphragm thicknesses, and experimentally examined the diaphragm thickness-dependent sensitivity.

    DOI: 10.23919/MOC.2017.8244579

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  • Optical distance measuring system using a laser diode's fast frequency noise as a detection signal 査読

    Suzuki Masamichi, Kasuya Yuki, Kawakami Daiki, Sato Takashi, Ohkawa Masashi, Ohdaira Yasuo, Sakamoto Shuichi

    MULTISPECTRAL, HYPERSPECTRAL, AND ULTRASPECTRAL REMOTE SENSING TECHNOLOGY, TECHNIQUES AND APPLICATIONS VII10780   2018年

  • Fast physical-random number generation for laser range finders using a laser diode's frequency noise -Comparison of the used lasers for fast random number generation- 査読

    Kasuya Yuki, Suzuki Masamichi, Matsumoto Kouhei, Arai Hideaki, Sato Takashi, Sakamoto Shuichi, Ohkawa Masashi, Ohdaira Yasuo

    MULTISPECTRAL, HYPERSPECTRAL, AND ULTRASPECTRAL REMOTE SENSING TECHNOLOGY, TECHNIQUES AND APPLICATIONS VII10780   2018年

  • Fast physical-random number generation using laser diode's frequency noise -Influence of frequency discriminator- 査読

    Matsumoto Kouhei, Kasuya Yuki, Yumoto Mitsuki, Arai Hideaki, Sato Takashi, Sakamoto Shuichi, Ohkawa Masashi, Ohdaira Yasuo

    PHYSICS AND SIMULATION OF OPTOELECTRONIC DEVICES XXVI10526   2018年

  • Physical-random number generator using an oscillation frequency stabilized laser diode 査読

    Hirai Kyohei, Taoka Toshihiro, Sato Takashi, Doi Kohei, Ohdaira Yasuo, Sakamoto Shuichi, Ohkawa Masashi

    PHYSICS AND SIMULATION OF OPTOELECTRONIC DEVICES XXVI10526   2018年

  • Optical distance measuring method using fast frequency noise characteristics of a laser diode 査読

    Kawakami Daiki, Suzuki Masamichi, Kimura Ryotaro, Sato Takashi, Saito Takahiro, Ohkawa Masashi, Ohdaira Yasuo, Sakamoto Shuichi

    PHYSICS AND SIMULATION OF OPTOELECTRONIC DEVICES XXVI10526   2018年

  • The status of DECIGO 査読

    Shuichi Sato, Seiji Kawamura, Masaki Ando, Takashi Nakamura, Kimio Tsubono, Akito Araya, Ikkoh Funaki, Kunihito Ioka, Nobuyuki Kanda, Shigenori Moriwaki, Mitsuru Musha, Kazuhiro Nakazawa, Kenji Numata, Shin Ichiro Sakai, Naoki Seto, Takeshi Takashima, Takahiro Tanaka, Kazuhiro Agatsuma, Koh Suke Aoyanagi, Koji Arai, Hideki Asada, Yoichi Aso, Takeshi Chiba, Toshikazu Ebisuzaki, Yumiko Ejiri, Motohiro Enoki, Yoshiharu Eriguchi, Masa Katsu Fujimoto, Ryuichi Fujita, Mitsuhiro Fukushima, Toshifumi Futamase, Katsuhiko Ganzu, Tomohiro Harada, Tatsuaki Hashimoto, Kazuhiro Hayama, Wataru Hikida, Yoshiaki Himemoto, Hisashi Hirabayashi, Takashi Hiramatsu, Feng Lei Hong, Hideyuki Horisawa, Mizuhiko Hosokawa, Kiyotomo Ichiki, Takeshi Ikegami, Kaiki T. Inoue, Koji Ishidoshiro, Hideki Ishihara, Takehiko Ishikawa, Hideharu Ishizaki, Hiroyuki Ito, Yousuke Itoh, Nobuki Kawashima, Fumiko Kawazoe, Naoko Kishimoto, Kenta Kiuchi, Shiho Kobayashi, Kazunori Kohri, Hiroyuki Koizumi, Yasufumi Kojima, Keiko Kokeyama, Wataru Kokuyama, Kei Kotake, Yoshihide Kozai, Hideaki Kudoh, Hiroo Kunimori, Hitoshi Kuninaka, Kazuaki Kuroda, Kei Ichi Maeda, Hideo Matsuhara, Yasushi Mino, Osamu Miyakawa, Shinji Miyoki, Mutsuko Y. Morimoto, Tomoko Morioka, Toshiyuki Morisawa, Shinji Mukohyama, Shigeo Nagano, Isao Naito, Kouji Nakamura, Hiroyuki Nakano, Kenichi Nakao, Shinichi Nakasuka, Yoshinori Nakayama, Erina Nishida, Kazutaka Nishiyama, Atsushi Nishizawa, Yoshito Niwa, Taiga Noumi, Yoshiyuki Obuchi, Masatake Ohashi, Naoko Ohishi, Masashi Ohkawa, Norio Okada, Kouji Onozato, Kenichi Oohara, Norichika Sago, Motoyuki Saijo, Masaaki Sakagami, Shihori Sakata, Misao Sasaki

    Journal of Physics: Conference Series840 ( 1 )   2017年6月

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    掲載種別:研究論文(国際会議プロシーディングス)  

    © Published under licence by IOP Publishing Ltd. DECIGO (DECi-hertz Interferometer Gravitational wave Observatory) is the planned Japanese space gravitational wave antenna, aiming to detect gravitational waves from astrophysically and cosmologically significant sources mainly between 0.1 Hz and 10 Hz and thus to open a new window for gravitational wave astronomy and for the universe. DECIGO will consists of three drag-free spacecraft arranged in an equilateral triangle with 1000 km arm lengths whose relative displacements are measured by a differential Fabry-Perot interferometer, and four units of triangular Fabry-Perot interferometers are arranged on heliocentric orbit around the sun. DECIGO is vary ambitious mission, we plan to launch DECIGO in era of 2030s after precursor satellite mission, B-DECIGO. B-DECIGO is essentially smaller version of DECIGO: B-DECIGO consists of three spacecraft arranged in an triangle with 100 km arm lengths orbiting 2000 km above the surface of the earth. It is hoped that the launch date will be late 2020s for the present..

    DOI: 10.1088/1742-6596/840/1/012010

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  • Study on the resolution improvement of a range finder using the chaotic frequency characteristics of a laser diode 査読

    Takahiro Saito, Shinya Maehara, Kohei Doi, Takashi Sato, Yasuo Ohdaira, Shuichi Sakamoto, Masashi Ohkawa

    OPTICAL ENGINEERING56 ( 6 ) 1 - 6   2017年6月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:SPIE-SOC PHOTO-OPTICAL INSTRUMENTATION ENGINEERS  

    An optical range finder system that relies on laser diodes' frequency noise, instead of intensity or frequency modulations, and its improvement in resolution are reported. The distance to the target is measured by calculating the cross-correlation of two signals reflected from the target and reference mirrors. These two signals are converted from the laser diodes' frequency noise signals by frequency/intensity converters, such as a Fabry-Perot etalon. We obtained the distance to the target by checking time lags between the target and reference beams at the highest correlation coefficient. We also measured the change in the correlation coefficient around the peak sampling point by adjusting the reference-path length, achieving a resolving power of +/- 3 mm. (C) The Authors. Published by SPIE under a Creative Commons Attribution 3.0 Unported License.

    DOI: 10.1117/1.OE.56.6.064101

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  • Design guidelines for a guided-wave optical pressure sensor based on dependences of sensitivity and resonance frequency on diaphragm dimensions 査読

    Hiroyuki Nikkuni, Masashi Ohkawa, Takashi Sato

    OPTICAL ENGINEERING56 ( 5 )   2017年5月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:SPIE-SOC PHOTO-OPTICAL INSTRUMENTATION ENGINEERS  

    Design guidelines for a guided-wave optical pressure sensor based on dependences of sensitivity and resonance frequency on diaphragm dimensions were considered. The guided-wave optical pressure sensor consists of a diaphragm and a single-mode waveguide on the diaphragm. According to our theoretical study, the edge of the diaphragm was found to be the best position to obtain the highest sensitivity. Also, sensitivity is proportional to the cube of the side length of the diaphragm but inversely proportional to the square of the diaphragm thickness. On the other hand, resonance frequency of the diaphragm is proportional to the diaphragm thickness and inversely proportional to the square of the side length. Dependences were experimentally examined for fabricated sensors with different diaphragm dimensions to confirm theoretical predictions. The experimental results agreed well with the theoretical predictions. Moreover, a design assistant chart for the sensor was proposed based on the dependences. (C) 2017 Society of Photo-Optical Instrumentation Engineers (SPIE)

    DOI: 10.1117/1.OE.56.5.057108

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  • Beat Signal Generation between Two Rubidium Absorption-Line-Stabilized Diode Lasers in GHz-Frequency Band 査読

    Tomoyuki Uehara, Shinya Maehara, Kohei Doi, Toshiya Nimonji, Takahiro Saito, Hideaki Arai, Takashi Sato, Yasuo Ohdaira, Shuichi Sakamoto, Masashi Ohkawa

    International Journal of Modern Physics and Applications2 ( 1 ) 1 - 6   2016年3月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    A stable microwave source using frequency stabilized diode lasers was developed. The Doppler-free spectra of Rb atoms produced by saturated absorption spectroscopy were used to obtain highly-sensitive control signals and lock the frequency of diode lasers to it. The beat frequencies between two independently stabilized diode lasers were 1.2 GHz and 2.9 GHz. The fluctuations in beat frequencies were 40 kHz and 400 kHz respectively in the best stability.

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  • Silicon-based guided-wave optical flow sensor using a diaphragm with a small opening as an orifice 査読

    Masashi Ohkawa, Takashi Sato

    OPTICAL ENGINEERING55 ( 1 )   2016年1月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:SPIE-SOC PHOTO-OPTICAL INSTRUMENTATION ENGINEERS  

    Our proposed silicon-based guided-wave optical flow sensor consists of a diaphragm with a small opening used as an orifice and a waveguide across the diaphragm. The sensor operates based on Bernoulli's theorem and the elasto-optic effect. A sensor, which had a 10 x 10-mm(2), 50-mu m-thick diaphragm with a 0.34 x 0.34-mm(2) opening, was fabricated to demonstrate and confirm the sensor operation. Measured output power as a function of flow rate using oxygen gas agreed quite well with the theoretical prediction although slight deviation was seen in the high flow rate region. Moreover, according to Bernoulli's theorem, sensitivity is strongly dependent on sectional area of opening. So, three sensors with different opening areas, such as 0.28 x 0.28, 0.34 x 0.34, and 0.55 x 0.55 mm(2), were fabricated to examine such a dependence, which would be helpful to design the sensor. The measured sensitivity was found to be almost proportional to area of the opening, similar to the theoretical prediction. (C) 2016 Society of Photo-Optical Instrumentation Engineers (SPIE)

    DOI: 10.1117/1.OE.55.1.017102

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  • Frequency noise characteristics of a diode laser and its application to physical random number generation

    Shinya Maehara, Kohei Kawakami, Hideaki Arai, Kenji Nakano, Kohei Doi, Takashi Sato, Yasuo Ohdaira, Shuichi Sakamoto, Masashi Ohkawa

    OPTICAL ENGINEERING52 ( 1 )   2013年1月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:SPIE-SOC PHOTO-OPTICAL INSTRUMENTATION ENGINEERS  

    We describe a method of generating physical random numbers by means of a diode laser that has an extremely wide-band frequency-noise profile. Fluctuations in the laser frequency affect the intensity of the light transmitted through the optical frequency discriminator, detected thereafter as random fluctuations. This allows us to simultaneously generate 8 random bit streams, due to the parallel processing of 8-digit binary numbers sampled by an 8-bit analog-to-digital converter. Finally, we generated physical random numbers at a rate of 3 Gbit/s, by combining one data stream with another stream that is delayed by 2 ms, by exclusive-OR. (C) The Authors. Published by SPIE under a Creative Commons Attribution 3.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI. [DOI: 10.1117/1.OE.52.1.014302]

    DOI: 10.1117/1.OE.52.1.014302

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  • Output Response Characteristics of Resonant-Type Guided-Wave Optical Acoustic Emission Sensor 査読

    Sotaro Tachibana, Masashi Ohkawa, Takashi Sato

    2013 IEEE SENSORS   1875 - 1878   2013年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:IEEE  

    Our group has proposed a resonant-type guided-wave optical acoustic emission (AE) sensor, which consists of a diaphragm and a single-mode optical waveguide on the diaphragm. In this study, we examined output response characteristics of the AE sensor using an acoustic sound pulse, instead of an AE pulse. Output responses of a fabricated AE sensor were investigated for each parameter, namely pulse duration, sound pressure (amplitude) and frequency. A larger output signal was obtained due to resonance effect, but it lacked similarity to the original target pulse due to a narrow bandwidth and required approximately 10 ms to reach the steady state. However, based on the experimental results, a formula was derived to determine pulse duration and amplitude. In the case of out-of-resonance, output signal is more complex, but the frequency deviation from the resonance frequency could be determined from the beat-like phenomenon for long-duration pulse.

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  • Scale-reduction rule without drop in the sensitivity of a silicon-based guided-wave optical pressure sensor using a micromachined diaphragm 査読

    Masashi Ohkawa, Takashi Sato

    OPTICAL ENGINEERING51 ( 1 ) 014401-1 - 6   2012年1月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:SPIE-SOC PHOTO-OPTICAL INSTRUMENTATION ENGINEERS  

    In this study, an original scale-reduction rule without a drop in the sensitivity of a guided-wave optical pressure sensor was obtained using a micromachined diaphragm. The sensor has a rectangular diaphragm as a pressure-sensitive structure and a sensing waveguide across the diaphragm. Its sensitivity is theoretically known to be strongly dependent on the dimensions of the diaphragm. According to the theoretical results, the sensitivity can be kept constant even if the diaphragm dimensions are reduced as long as both the aspect ratio and the characteristic length of the diaphragm remain constant. Here, the characteristic length is introduced as the cube of either width or length of the rectangular diaphragm divided by the square of its thickness. Such a scale-reduction rule would be very useful for miniaturizing a sensor without reducing sensitivity, although it has not been experimentally confirmed. In this study, the scale-reduction rule was experimentally examined using three fabricated sensors with the same aspect ratio and the same characteristic length. The measured sensitivities of the three sensors were quite similar to each other, as theoretically predicted. (C) 2012 Society of Photo-Optical Instrumentation Engineers (SPIE). [DOI: 10.1117/1.OE.51.1.014401]

    DOI: 10.1117/1.OE.51.1.014401

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  • Oscillation wavelength shifts observed in vertical cavity surface emitting lasers exposed to magnetic fields

    Y. Yamagishi, S. Tabira, Y. Matsumoto, K. Doi, T. Sato, M. Ohkawa

    PHYSICS AND SIMULATION OF OPTOELECTRONIC DEVICES XX8255   825522   2012年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:SPIE-INT SOC OPTICAL ENGINEERING  

    Even as long ago as the 1960's, scientists understood that diode lasers' oscillation wavelengths demonstrated significant shifts to the shorter wavelength side, when subjected to strong magnetic fields, at extremely low temperatures. When we exposed Fabry-Perot type diode lasers oscillating at 780 nm to weak magnetic fields, at room temperature, the oscillation wavelength was observed to have shifted to the longer wavelength side. In discussions of shift mechanisms aimed at explaining how/why our results differ from those obtained in studies conducted in the 1960's, we noted a rise in temperature and an increase in the carrier density, and how it affected the characteristic shifts observed, when a magnetic field was applied to the Fabry-Perot type laser diodes parallel to the injection current. In the present work, we tested the oscillation wavelength shift of a vertical-cavity surface-emitting laser (VCSEL) in a magnetic field, because we expected that, by doing so, the VCSEL would show a shorter wavelength side shift.

    DOI: 10.1117/12.908016

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  • Fast Random-Number Generation Using a Diode Laser's Frequency Noise Characteristic

    Hiroki Takamori, Kohei Doi, Shinya Maehara, Kohei Kawakami, Takashi Sato, Masashi Ohkawa, Yasuo Odaira

    PHYSICS AND SIMULATION OF OPTOELECTRONIC DEVICES XX8255   825521   2012年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:SPIE-INT SOC OPTICAL ENGINEERING  

    Random numbers can be classified as either pseudo- or physical-random, in character. Pseudo-random numbers are generated by definite periodicity, so, their usefulness in cryptographic applications is somewhat limited. On the other hand, naturally-generated physical-random numbers have no calculable periodicity, thereby making them ideal for the task. Diode lasers' considerable wideband noise gives them tremendous capacity for generating physical-random numbers, at a high rate of speed. We measured a diode laser's output with a fast photo detector, and evaluated the binary-numbers from the diode laser's frequency noise characteristics. We then identified and evaluated the binary-number-line's statistical properties. We also investigate the possibility that much faster physical-random number parallel-generation is possible, using separate outputs of different optical-path length and character, which we refer to as "coherence collapse".

    DOI: 10.1117/12.908011

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  • Oscillation frequency stabilization and narrowing of a laser diode by using an external cavity

    Minoru Iwahori, Kohei Doi, Hideaki Arai, Takashi Sato, Masashi Ohkawa

    PHYSICS AND SIMULATION OF OPTOELECTRONIC DEVICES XX8255   825529   2012年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:SPIE-INT SOC OPTICAL ENGINEERING  

    External cavity diode laser (ECDL) systems are presently experiencing a surge in popularity as laser light-sources, in advanced optical communications- and measurement-applications. Because such systems require that their external reflectors be precisely controlled, to eliminate low frequency fluctuations in optical output, we conducted experiments with a two-cavity version of the ECDL system for a vertical cavity surface emitting laser (VCSEL). This technique brings the added advantages of a narrower linewidth than would be achievable via a single optical feedback. VCSELs are characterized by wider oscillation linewidths than edge emitting types, so the larger effect of double optical feedback system is expected.

    DOI: 10.1117/12.909622

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  • THz wave generation using frequency stabilized laser diodes

    Yasuhito Minamisawa, Tosiya Nimonji, Kenji Nakano, Takashi Sato, Masashi Ohkawa

    PHYSICS AND SIMULATION OF OPTOELECTRONIC DEVICES XX8255   82551L   2012年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:SPIE-INT SOC OPTICAL ENGINEERING  

    A laser diode (LD) has been used in many areas, such as optical communication systems. However, its oscillation frequency changes, with variations in ambient temperature and injection current, so its frequency stabilization is of vital importance. In these situations, Rb saturated absorption spectroscopy is the method of choice. We use the beat signal, both for the purpose of evaluating frequency stability between two independently stabilized LDs, and for generating THz waves. This work shows a basic experiment using our beat signal observation, by high-speed photodetector. In addition, we have also used a frequency-stabilized etalon, to improve frequency selectivity.

    DOI: 10.1117/12.908275

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  • Evaluation of Damping Ratio in a Glass-Based Guided-Wave Optical Microphone with a Diaphragm

    Masashi Ohkawa, Kazuya Murata, Takashi Sato

    INTEGRATED OPTICS: DEVICES, MATERIALS, AND TECHNOLOGIES XVI8264   82641I   2012年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:SPIE-INT SOC OPTICAL ENGINEERING  

    In a guided-wave optical microphone with a diaphragm used as a vibration plate, damping of diaphragm vibration is very significant in order to realize broad flat frequency response. In this study, a glass-based guided-wave optical microphone without a damping structure was experimentally examined to evaluate the damping ratio as the first phase in the optimization of damping. Damping ratio and resonance frequency were successfully evaluated to be 0.009 and 3.5 kHz, respectively, for a fabricated microphone with a diaphragm of 20 mm x 20 mm x 0.15 mm.

    DOI: 10.1117/12.910286

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  • Silicon-Based Guided-Wave Optical Accelerometer: Experimental Consideration to Establish its Design Guideline

    Natsumi Saito, Yusuke Miura, Takuya Oshima, Masashi Ohkawa, Takashi Sato

    2012 IEEE SENSORS PROCEEDINGS   453 - 456   2012年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:IEEE  

    Our group has proposed and demonstrated a silicon-based guided-wave optical accelerometer with a proof mass centered on a diaphragm. It is strongly suggested that sensitivity is related to many factors, such as waveguide position, diaphragm dimensions, and size and weight of proof mass. These relationships need to be clearly identified in order to establish a design guideline. In this study, sensitivity dependences on waveguide position and diaphragm dimensions were experimentally examined. Regarding waveguide position, phase sensitivity was highest for the waveguide at the diaphragm edge, and was also relatively high for the waveguide at the edge of proof mass. Regarding diaphragm dimensions, phase sensitivity was found to be inversely proportional to the square of the diaphragm thickness, and proportional to the side length of the diaphragm.

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  • Design Study of a Guided-Wave Optical Microphone with a Diaphragm

    Kazuya Murata, Masashi Ohkawa, Takashi Sato

    2012 IEEE SENSORS PROCEEDINGS   2160 - 2163   2012年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:IEEE  

    Our guided-wave optical microphone consists of a diaphragm and a single-mode optical waveguide on the diaphragm. Since sensitivity and frequency response are strongly dependent on waveguide position and diaphragm dimensions, designing the microphone is relatively complicated without a design guideline. In this report, a convenient and helpful chart diagram when designing the microphone is proposed based on theoretical and experimental results on dependences of sensitivity and resonance frequency on diaphragm dimensions. In addition, since damping of diaphragm vibration is also vital in obtaining a broader flat frequency response, squeeze-film air damping is discussed.

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  • Damping ratio in a glass-based guided-wave optical microphone without a damping structure

    Kazuya Murata, Kazuaki Yoshida, Masashi Ohkawa, Takashi Sato

    Technical Digest of the 17th Microooptics Conference   H-59   2011年11月

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)  

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  • The Japanese space gravitational wave antenna: DECIGO 査読

    Seiji Kawamura, Masaki Ando, Naoki Seto, Shuichi Sato, Takashi Nakamura, Kimio Tsubono, Nobuyuki Kanda, Takahiro Tanaka, Jun'ichi Yokoyama, Ikkoh Funaki, Kenji Numata, Kunihito Ioka, Takeshi Takashima, Kazuhiro Agatsuma, Tomotada Akutsu, Koh-suke Aoyanagi, Koji Arai, Akito Araya, Hideki Asada, Yoichi Aso, Dan Chen, Takeshi Chiba, Toshikazu Ebisuzaki, Yumiko Ejiri, Motohiro Enoki, Yoshiharu Eriguchi, Masa-Katsu Fujimoto, Ryuichi Fujita, Mitsuhiro Fukushima, Toshifumi Futamase, Tomohiro Harada, Tatsuaki Hashimoto, Kazuhiro Hayama, Wataru Hikida, Yoshiaki Himemoto, Hisashi Hirabayashi, Takashi Hiramatsu, Feng-Lei Hong, Hideyuki Horisawa, Mizuhiko Hosokawa, Kiyotomo Ichiki, Takeshi Ikegami, Kaiki T. Inoue, Koji Ishidoshiro, Hideki Ishihara, Takehiko Ishikawa, Hideharu Ishizaki, Hiroyuki Ito, Yousuke Itoh, Kiwamu Izumi, Isao Kawano, Nobuki Kawashima, Fumiko Kawazoe, Naoko Kishimoto, Kenta Kiuchi, Shiho Kobayashi, Kazunori Kohri, Hiroyuki Koizumi, Yasufumi Kojima, Keiko Kokeyama, Wataru Kokuyama, Kei Kotake, Yoshihide Kozai, Hiroo Kunimori, Hitoshi Kuninaka, Kazuaki Kuroda, Sachiko Kuroyanagi, Kei-ichi Maeda, Hideo Matsuhara, Nobuyuki Matsumoto, Yuta Michimura, Osamu Miyakawa, Umpei Miyamoto, Shinji Miyoki, Mutsuko Y. Morimoto, Toshiyuki Morisawa, Shigenori Moriwaki, Shinji Mukohyama, Mitsuru Musha, Shigeo Nagano, Isao Naito, Kouji Nakamura, Hiroyuki Nakano, Kenichi Nakao, Shinichi Nakasuka, Yoshinori Nakayama, Kazuhiro Nakazawa, Erina Nishida, Kazutaka Nishiyama, Atsushi Nishizawa, Yoshito Niwa, Taiga Noumi, Yoshiyuki Obuchi, Masatake Ohashi, Naoko Ohishi, Masashi Ohkawa, Kenshi Okada, Norio Okada, Kenichi Oohara, Norichika Sago, Motoyuki Saijo, Ryo Saito, Masaaki Sakagami, Shin-ichiro Sakai, Shihori Sakata, Misao Sasaki, Takashi Sato, Masaru Shibata, Hisaaki Shinkai, Ayaka Shoda, Kentaro Somiya, Hajime Sotani, Naoshi Sugiyama, Yudai Suwa, Rieko Suzuki, Hideyuki Tagoshi, Fuminobu Takahashi, Kakeru Takahashi, Keitaro Takahashi, Ryutaro Takahashi, Ryuichi Takahashi, Tadayuki Takahashi, Hirotaka Takahashi, Takamori Akiteru, Tadashi Takano, Nobuyuki Tanaka, Keisuke Taniguchi, Atsushi Taruya, Hiroyuki Tashiro, Yasuo Torii, Morio Toyoshima, Shinji Tsujikawa, Yoshiki Tsunesada, Akitoshi Ueda, Ken-ichi Ueda, Masayoshi Utashima, Yaka Wakabayashi, Kent Yagi, Hiroshi Yamakawa, Kazuhiro Yamamoto, Toshitaka Yamazaki, Chul-Moon Yoo, Shijun Yoshida, Taizoh Yoshino, Ke-Xun Sun

    CLASSICAL AND QUANTUM GRAVITY28 ( 9 ) 094011   2011年5月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:IOP PUBLISHING LTD  

    The objectives of the DECi-hertz Interferometer Gravitational Wave Observatory (DECIGO) are to open a new window of observation for gravitational wave astronomy and to obtain insight into significant areas of science, such as verifying and characterizing inflation, determining the thermal history of the universe, characterizing dark energy, describing the formation mechanism of supermassive black holes in the center of galaxies, testing alternative theories of gravity, seeking black hole dark matter, understanding the physics of neutron stars and searching for planets around double neutron stars. DECIGO consists of four clusters of spacecraft in heliocentric orbits; each cluster employs three drag-free spacecraft, 1000 km apart from each other, whose relative displacements are measured by three pairs of differential Fabry-Perot Michelson interferometers. Two milestone missions, DECIGO pathfinder and Pre-DECIGO, will be launched to demonstrate required technologies and possibly to detect gravitational waves.

    DOI: 10.1088/0264-9381/28/9/094011

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  • Super fast physical-random number generation using laser diode frequency noises

    Tetsuro Ushiki, Kohei Doi, Shinya Maehara, Takashi Sato, Masashi Ohkawa, Yasuo Ohdaira

    PHYSICS AND SIMULATION OF OPTOELECTRONIC DEVICES XIX7933   79332F   2011年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:SPIE-INT SOC OPTICAL ENGINEERING  

    Random numbers can be classified as either pseudo- or physical-random in character. Pseudo-random numbers' periodicity renders them inappropriate for use in cryptographic applications, but naturally-generated physical-random numbers have no calculable periodicity, thereby making them ideally-suited to the task. The laser diode naturally produces a wideband "noise" signal that is believed to have tremendous capacity and great promise, for the rapid generation of physical-random numbers for use in cryptographic applications. We measured a laser diode's output, at a fast photo detector and generated physical-random numbers from frequency noises. We then identified and evaluated the binary-number-line's statistical properties. The result shows that physical-random number generation, at speeds as high as 40Gbps, is obtainable, using the laser diode's frequency noise characteristic.

    DOI: 10.1117/12.875830

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  • Consideration of sensitivity with respect to diaphragm thickness and waveguide position in silicon-based guided-wave optical accelerometer

    Yusuke Miura, Hideto Endo, Takuya Oshima, Masashi Ohkawa, Takashi Sato

    INTEGRATED OPTICS: DEVICES, MATERIALS, AND TECHNOLOGIES XV7941   79410P   2011年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:SPIE-INT SOC OPTICAL ENGINEERING  

    Our group has developed a silicon-based guided-wave optical accelerometer with a proof mass centered on a diaphragm. For this type of accelerometer, it is strongly suggested that sensitivity is related to waveguide position, diaphragm dimensions, and size and weight of proof mass. In this study, sensitivity dependences on waveguide position and diaphragm thickness were considered experimentally. Experimental results demonstrated that the highest sensitivity could be obtained for the waveguide at the diaphragm edge and is inversely proportional to the square of the diaphragm thickness.

    DOI: 10.1117/12.873660

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  • Oscillation frequency shifts observed in vertical cavity surface emitting lasers exposed to magnetic fields

    T. Kobayashi, Y. Yamagishi, H. Arai, Y. Matsumoto, T. Sato, M. Ohkawa

    PHYSICS AND SIMULATION OF OPTOELECTRONIC DEVICES XIX7933   79331O   2011年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:SPIE-INT SOC OPTICAL ENGINEERING  

    As long ago as the 1960's, scientists understood that Diode lasers' oscillation wavelengths showed a significant shift to the shorter wavelength (high frequency) side, when exposed to strong (<4[T]) magnetic fields, at extremely low temperatures (<80[K]). Not surprisingly, then, in preliminary tests, when we exposed Fabry/Perot-type diode lasers oscillating at 780[nm] to weak magnetic fields (<1.4[T]), at room temperature (300[K]), we observed that the oscillation wavelength shifted to the longer (low frequency) wavelength side. In the present work, we used vertical-cavity surface-emitting lasers (VCSEL) to check whether its change into the shorter wavelength side takes place.
    In discussions of shift mechanisms, we consider how wavelength (frequency) and optical output-power shifts are correlated. Our expanded knowledge base has forced us to use a completely different mechanism to explain how/why our results differ from those obtained in studies conducted in the 1960's. We are now introducing a mechanism that affects a rise in temperature and an increase in the carrier density, affect the characteristic shifts observed in our experiments, when a magnetic field is applied to the laser diodes parallel to the injection current.

    DOI: 10.1117/12.875851

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  • Modeling of fluid dynamics and thermo-chemical system in halogen lamp operation 査読

    Makoto Bessho, Masashi Ohkawa

    Journal of Light and Visual Environment35 ( 1 ) 7 - 22   2011年

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    One of the key elements in improving lamp efficiency is understanding and controlling the halogen transport process. Therefore, it is worthwhile to build a model that depicts this process and can be applied to the study of various types of lamps. We examined the halogen transport process in a lamp by using a hybrid simulation model based on fluid dynamics and chemical equilibrium.

    DOI: 10.2150/jlve.35.7

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  • Examination of tungsten transport in operating halogen lamp by fluid dynamics and thermo chemical simulation 査読

    Makoto Bessho, Masashi Ohkawa

    Journal of Light and Visual Environment35 ( 1 ) 23 - 33   2011年

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    Tungsten transport in halogen lamp operation was examined by fluid dynamics and thermo-chemical simulation. Partial pressures of almost all species dramatically increased around the coil leads. The cause appears to be a stagnant flow of filling gases. Results of a life test showed that tungsten was slightly deposited at the coil leads. Such a tungsten deposit can be attributed to a high concentration of tungsten compounds during the gas phase.

    DOI: 10.2150/jlve.35.23

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  • Sensitivity dependences on waveguide position and diaphragm thickness in silicon-based guided-wave optical accelerometer

    Masashi Ohkawa, Hideto Endo, Takuya Oshima, Yusuke Miura, Takashi Sato

    Technical Digest of the 16th Microooptics Conference   WP-30   2010年11月

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)  

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  • Double External Cavity Single-Mode VCSEL system for DWDM applications

    Kohei Doi, Hideaki Arai, Shinya Maehara, Takashi Sato, Masashi Ohkawa

    International Symposium on Organic and Inorganic Electronic Materials and Related Nanotechnologies (EM-NANO2010)   B1-2   2010年6月

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)  

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  • Physical-Random Number Generation Using Frequency Noises of Laser Diode

    Shinya Maehara, Kohei Doi, Takashi Sato, Yasuo Ohdaira, Masashi Ohkawa

    International Symposium on Organic and Inorganic Electronic Materials and Related Nanotechnologies (EM-NANO2010)   P3-12   2010年6月

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)  

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  • DECIGO and DECIGO pathfinder 査読

    Masaki Ando, Seiji Kawamura, Naoki Seto, Shuichi Sato, Takashi Nakamura, Kimio Tsubono, Takeshi Takashima, Ikkoh Funaki, Kenji Numata, Nobuyuki Kanda, Takahiro Tanaka, Kunihito Ioka, Kazuhiro Agatsuma, Koh-suke Aoyanagi, Koji Arai, Akito Araya, Hideki Asada, Yoichi Aso, Takeshi Chiba, Toshikazu Ebisuzaki, Yumiko Ejiri, Motohiro Enoki, Yoshiharu Eriguchi, Masa-Katsu Fujimoto, Ryuichi Fujita, Mitsuhiro Fukushima, Toshifumi Futamase, Tomohiro Harada, Tatsuaki Hashimoto, Kazuhiro Hayama, Wataru Hikida, Yoshiaki Himemoto, Hisashi Hirabayashi, Takashi Hiramatsu, Feng-Lei Hong, Hideyuki Horisawa, Mizuhiko Hosokawa, Kiyotomo Ichiki, Takeshi Ikegami, Kaiki T. Inoue, Koji Ishidoshiro, Hideki Ishihara, Takehiko Ishikawa, Hideharu Ishizaki, Hiroyuki Ito, Yousuke Itoh, Kiwamu Izumi, Isao Kawano, Nobuki Kawashima, Fumiko Kawazoe, Naoko Kishimoto, Kenta Kiuchi, Shiho Kobayashi, Kazunori Kohri, Hiroyuki Koizumi, Yasufumi Kojima, Keiko Kokeyama, Wataru Kokuyama, Kei Kotake, Yoshihide Kozai, Hiroo Kunimori, Hitoshi Kuninaka, Kazuaki Kuroda, Kei-ichi Maeda, Hideo Matsuhara, Yasushi Mino, Osamu Miyakawa, Umpei Miyamoto, Shinji Miyoki, Mutsuko Y. Morimoto, Toshiyuki Morisawa, Shigenori Moriwaki, Shinji Mukohyama, Mitsuru Musha, Shigeo Nagano, Isao Naito, Kouji Nakamura, Masahiro Nakamura, Hiroyuki Nakano, Kenichi Nakao, Shinichi Nakasuka, Yoshinori Nakayama, Kazuhiro Nakazawa, Erina Nishida, Kazutaka Nishiyama, Atsushi Nishizawa, Yoshito Niwa, Taiga Noumi, Yoshiyuki Obuchi, Masatake Ohashi, Naoko Ohishi, Masashi Ohkawa, Kenshi Okada, Norio Okada, Kenichi Oohara, Norichika Sago, Motoyuki Saijo, Ryo Saito, Masaaki Sakagami, Shin-ichiro Sakai, Shihori Sakata, Misao Sasaki, Takashi Sato, Masaru Shibata, Hisaaki Shinkai, Kentaro Somiya, Hajime Sotani, Naoshi Sugiyama, Yudai Suwa, Rieko Suzuki, Hideyuki Tagoshi, Fuminobu Takahashi, Kakeru Takahashi, Keitaro Takahashi, Ryutaro Takahashi, Ryuichi Takahashi, Tadayuki Takahashi, Hirotaka Takahashi, Takamori Akiteru, Tadashi Takano, Keisuke Taniguchi, Atsushi Taruya, Hiroyuki Tashiro, Yasuo Torii, Morio Toyoshima, Shinji Tsujikawa, Yoshiki Tsunesada, Akitoshi Ueda, Ken-ichi Ueda, Masayoshi Utashima, Yaka Wakabayashi, Kent Yagi, Hiroshi Yamakawa, Kazuhiro Yamamoto, Toshitaka Yamazaki, Jun'ichi Yokoyama, Chul-Moon Yoo, Shijun Yoshida, Taizoh Yoshino, Ken-Xun Sun

    CLASSICAL AND QUANTUM GRAVITY27 ( 8 )   2010年4月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:IOP PUBLISHING LTD  

    A space gravitational-wave antenna, DECIGO (DECI-hertz interferometer Gravitational wave Observatory), will provide fruitful insights into the universe, particularly on the formation mechanism of supermassive black holes, dark energy and the inflation of the universe. In the current pre-conceptual design, DECIGO will be comprising four interferometer units; each interferometer unit will be formed by three drag-free spacecraft with 1000 km separation. Since DECIGO will be an extremely challenging mission with high-precision formation flight with long baseline, it is important to increase the technical feasibility before its planned launch in 2027. Thus, we are planning to launch two milestone missions. DECIGO pathfinder (DPF) is the first milestone mission, and key components for DPF are being tested on ground and in orbit. In this paper, we review the conceptual design and current status of DECIGO and DPF.

    DOI: 10.1088/0264-9381/27/8/084010

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    その他リンク: http://orcid.org/0000-0003-1318-2635

  • Double optical feedback system for a single-mode vertical-cavity surface-emitting laser 査読

    Kohei Doi, Takashi Sato, Masashi Ohkawa

    OPTICAL ENGINEERING49 ( 1 ) 014202   2010年1月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:SPIE-SOC PHOTOPTICAL INSTRUMENTATION ENGINEERS  

    Ongoing tests involving the application of double optical feedback to a vertical-cavity surface-emitting laser (VCSEL) are resulting in demonstrable and significant improvements in oscillation linewidth and frequency stability. We look into the workings of a double optical feedback system for a Fabry-Perot-type diode laser. We describe a single-mode VCSEL that is characterized by a narrow oscillation linewidth and a stable output intensity that shows no trace of the low-frequency fluctuation (LFF) that so often occurs in single optical feedback diode lasers. Initial tests use a beat note to do this. From there, we calculate the square root of the Allan variance to determine the level of frequency stability. We also evaluate the degree of LFF suppression achieved using its spectrum density and compare those results with what we obtained through single and double optical feedback and with no feedback whatsoever. (C) 2010 Society of Photo-Optical Instrumentation Engineers. [DOI: 10.1117/1.3284784]

    DOI: 10.1117/1.3284784

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  • Frequency stabilization of a laser diode using Rb saturated absorption lines

    Ayumi Sato, Kenji Nakano, Hideaki Arai, Takashi Sato, Masashi Ohkawa

    PHYSICS AND SIMULATION OF OPTOELECTRONIC DEVICES XVIII7597   79571N   2010年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:SPIE-INT SOC OPTICAL ENGINEERING  

    We have succeeded, thus far, in stabilizing laser diode (LD) frequencies to Rb absorption lines, by means of negative electrical feedback. While the absorption lines were stable over the long term, the Doppler Effect's influence was evident, in broadened spectrum linewidth. To avoid the problem in subsequent tests, we used Rb-saturated absorption signals.
    In this work, we demonstrated potentials of two applications; one was as a reference signal source for estimation of other LD's frequency stabilization system, and the other was a light source for generation of THz radiation.

    DOI: 10.1117/12.840610

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  • VCSEL's frequency stabilization of an external cavity diode laser - Countermeasures against atmospheric temperature variations

    Mutsuki Motojima, Kohei Doi, Takashi Sato, Masashi Ohkawa, Takamasa Suzuki

    PHYSICS AND SIMULATION OF OPTOELECTRONIC DEVICES XVIII7597   75972A   2010年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:SPIE-INT SOC OPTICAL ENGINEERING  

    We introduced the vertical cavity surface emitting laser (VCSEL) as the laser diode in tour external cavity system. Because VCSELs are now commercially available, and the External cavity diode laser (ECDL) systems using them are expected to improve their frequency stability, we have replaced a Fabry-Perot type laser diode with a VCSEL, and examined its oscillation-frequency stability. Therefore we were able to expect that the VCSELs with our double optical feedback system have good oscillation frequency stability. The obtained VCSEL's oscillation-frequency stability, i.e., the square root of Allan variance sigma was 4x10(-10), at an averaging time of tau = 1 sec.

    DOI: 10.1117/12.840609

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  • Physical-random number generation using laser diodes' inherent noises

    Hiroki Nishimura, Kohei Doi, Tetsurou Ushiki, Takashi Sato, Masashi Ohkawa, Yasuo Odaira

    PHYSICS AND SIMULATION OF OPTOELECTRONIC DEVICES XVIII7597   75970M   2010年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:SPIE-INT SOC OPTICAL ENGINEERING  

    Random numbers can be classified as either pseudo- or physical-random in character. This work demonstrates how laser diodes' inherent noise can be exploited for use in generating physical-random numbers in cryptographic applications. In the initial stages of the experiment, we measured a laser diode's output, at a fast photo detector and generated physical-random numbers from intensity noises. We then identified and evaluated the binary-number-line's statistical properties. Our preliminary results show that fast physical-random numbers are obtainable, using the laser diode's frequency noise characteristics.

    DOI: 10.1117/12.840626

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  • Semiconductor laser oscillation-frequency stabilization using the Faraday effect

    Hideaki Arai, Akira Sato, Ayumi Sato, Kenji Nakano, Takashi Sato, Masashi Ohkawa

    PHYSICS AND SIMULATION OF OPTOELECTRONIC DEVICES XVIII7597   75971D   2010年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:SPIE-INT SOC OPTICAL ENGINEERING  

    The semiconductor lasers in use today are on one hand, prized, and highly praised, for their small size, light weight, longevity and energy-efficiency, -and on the other, criticized for their susceptibility to frequency-fluctuations brought about by changes in temperature and driving current. Once this "wrinkle" is ironed out, semiconductor lasers will become the default light-sources, for satellites' onboard interferometers. Our studies have been directed at stabilizing oscillation frequency to the atomic absorption line, and using negative electrical feedback to the injection current. Frequency stabilization is accomplished, by either; a) applying direct modulation to the semiconductor laser's driving current, or b) modulating the reference frequency, to obtain the error signal needed for stabilization. In this instance, Faraday effect-based stabilization was used. This indirect oscillation frequency stabilization has no discernable effect on spectra width, but, stability was no better than that observed in the system using the direct modulation.
    When we compared Faraday effect-and direct modulation-based methods of stabilization, in order to uncover the root-cause of the discrepancy, sensors picked up system noise, the source of which was heat generated by the heavy current applied to a magnetic coil used to apply the Faraday effect. We also substituted a permanent magnet for the electromagnet.

    DOI: 10.1117/12.841526

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  • Characteristics of a glass-based guided-wave optical microphone

    Hiroyuki Nikkuni, Masashi Ohkawa, Takashi Sato

    Technical Digest of the 15th Microoptics Conference   296 - 297   2009年10月

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)  

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  • Diaphragm size-dependent resonance frequency in a glass-based optical microphone

    Mizuki Nakajima, Hiroyuki Nikkuni, Masashi Ohkawa, Takashi Sato

    Technical Digest of the 15th Microoptics Conference   298 - 299   2009年10月

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)  

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  • Sensitivity dependences of silicon-based guided-wave optical flow sensors

    Masashi Ohkawa, Yusuke Kudo, Masafumi Adachi, Takashi Sato

    Integrated Photonics and Nanophotonics Research and Applications (IPNRA) 2009   JTuB7   2009年7月

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)  

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  • DECIGO pathfinder 査読

    Masaki Ando, Seiji Kawamura, Shuichi Sato, Takashi Nakamura, Kimio Tsubono, Akito Araya, Ikkoh Funaki, Kunihito Ioka, Nobuyuki Kanda, Shigenori Moriwaki, Mitsuru Musha, Kazuhiro Nakazawa, Kenji Numata, Shin-ichiro Sakai, Naoki Seto, Takeshi Takashima, Takahiro Tanaka, Kazuhiro Agatsuma, Koh-suke Aoyanagi, Koji Arai, Hideki Asada, Yoichi Aso, Takeshi Chiba, Toshikazu Ebisuzaki, Yumiko Ejiri, Motohiro Enoki, Yoshiharu Eriguchi, Masa-Katsu Fujimoto, Ryuichi Fujita, Mitsuhiro Fukushima, Toshifumi Futamase, Katsuhiko Ganzu, Tomohiro Harada, Tatsuaki Hashimoto, Kazuhiro Hayama, Wataru Hikida, Yoshiaki Himemoto, Hisashi Hirabayashi, Takashi Hiramatsu, Feng-Lei Hong, Hideyuki Horisawa, Mizuhiko Hosokawa, Kiyotomo Ichiki, Takeshi Ikegami, Kaiki T. Inoue, Koji Ishidoshiro, Hideki Ishihara, Takehiko Ishikawa, Hideharu Ishizaki, Hiroyuki Ito, Yousuke Itoh, Nobuki Kawashima, Fumiko Kawazoe, Naoko Kishimoto, Kenta Kiuchi, Shiho Kobayashi, Kazunori Kohri, Hiroyuki Koizumi, Yasufumi Kojima, Keiko Kokeyama, Wataru Kokuyama, Kei Kotake, Yoshihide Kozai, Hideaki Kudoh, Hiroo Kunimori, Hitoshi Kuninaka, Kazuaki Kuroda, Kei-ichi Maeda, Hideo Matsuhara, Yasushi Mino, Osamu Miyakawa, Shinji Miyoki, Mutsuko Y. Morimoto, Tomoko Morioka, Toshiyuki Morisawa, Shinji Mukohyama, Shigeo Nagano, Isao Naito, Kouji Nakamura, Hiroyuki Nakano, Kenichi Nakao, Shinichi Nakasuka, Yoshinori Nakayama, Erina Nishida, Kazutaka Nishiyama, Atsushi Nishizawa, Yoshito Niwa, Taiga Noumi, Yoshiyuki Obuchi, Masatake Ohashi, Naoko Ohishi, Masashi Ohkawa, Norio Okada, Kouji Onozato, Kenichi Oohara, Norichika Sago, Motoyuki Saijo, Masaaki Sakagami, Shihori Sakata, Misao Sasaki, Takashi Sato, Masaru Shibata, Hisaaki Shinkai, Kentaro Somiya, Hajime Sotani, Naoshi Sugiyama, Yudai Suwa, Rieko Suzuki, Hideyuki Tagoshi, Fuminobu Takahashi, Kakeru Takahashi, Keitaro Takahashi, Ryutaro Takahashi, Ryuichi Takahashi, Tadayuki Takahashi, Hirotaka Takahashi, Takamori Akiteru, Tadashi Takano, Keisuke Taniguchi, Atsushi Taruya, Hiroyuki Tashiro, Yasuo Torii, Morio Toyoshima, Shinji Tsujikawa, Yoshiki Tsunesada, Akitoshi Ueda, Ken-ichi Ueda, Masayoshi Utashima, Yaka Wakabayashi, Hiroshi Yamakawa, Kazuhiro Yamamoto, Toshitaka Yamazaki, Jun'ichi Yokoyama, Chul-Moon Yoo, Shijun Yoshida, Taizoh Yoshino

    CLASSICAL AND QUANTUM GRAVITY26 ( 9 )   2009年5月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:IOP PUBLISHING LTD  

    DECIGO pathfinder (DPF) is a milestone satellite mission for DECIGO (DECi-hertz Interferometer Gravitational wave Observatory), which is a future space gravitational wave antenna. DECIGO is expected to provide fruitful insights into the universe, particularly about dark energy, the formation mechanism of supermassive black holes and the inflation of the universe. Since DECIGO will be an extremely challenging mission, which will be formed by three drag-free spacecraft with 1000 km separation, it is important to increase the technical feasibility of DECIGO before its planned launch in 2024. Thus, we are planning to launch two milestone missions: DPF and pre-DECIGO. In this paper, we review the conceptual design and current status of the first milestone mission, DPF.

    DOI: 10.1088/0264-9381/26/9/094019

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    その他リンク: http://orcid.org/0000-0003-1318-2635

  • Comparison of three semiconductor laser systems for gravitational wave detection 査読

    Tomoyuki Uehara, Akira Sato, Shinya Maehara, Toshiya Nimonji, Takashi Sato, Masashi Ohkawa, Takeo Maruyama, Seiji Kawamura

    OPTICAL ENGINEERING48 ( 3 ) 034302   2009年3月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:SPIE-SOC PHOTOPTICAL INSTRUMENTATION ENGINEERS  

    The primary objective of the Decihertz Interferometer Gravitational Wave Observatory (DECIGO) mission is to detect and observe black holes' and galactic binaries' gravitational waves (GWs), at frequencies ranging from 10(-2) to 10(1) Hz (from 0.1 to 100 s in averaging time). This low-frequency range is inaccessible to ground-based interferometers, due to unshieldable background noise and to the fact that ground-based interferometers are limited to a few kilometers in length. Our research is focused on efforts to stabilize semiconductor, Nd:YAG, and fiber lasers, for use as GW detectors' optical sources. In present-day and future detectors, frequency and phase noise may place certain limitations on sensitivity and stability. Our goal is primarily to design robust experiments. In this report, we compare existing methods: Faraday, Faraday peak, and saturated absorption spectroscopy. In these, the laser frequency is stabilized to Rb as an atomic frequency reference by a feedback-loop control system. From the frequency stability of these models, we can predict the characteristics of the three systems through dynamic stability analysis, by analyzing the dynamic Allan variance. We find the optical frequency stability, expressed as the Allan deviation (the square root of the Allan variance), to be 3.3 x 10(-11), 2.9 x 10(-12), and 1.2 x 10(-12) in the respective methods. (C) 2009 Society of Photo-Optical Instrumentation Engineers. [DOI: 10.1117/1.3089887]

    DOI: 10.1117/1.3089887

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  • Modeling of fluid dynamics and thermo chemical system in operating halogen lamp

    Makoto Bessho, Masashi Ohkawa

    Lux Pacifica Conference 2009   197 - 202   2009年1月

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)  

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  • 平成20年度リフレッシュ理科教室(北陸・信越支部新潟会場)開催報告 査読

    大河正志, 鈴木孝昌, 坪井望, 新保一成, 大平泰生, 馬場暁, 岩野春男, 丸山武男

    応用物理教育33 ( 1 ) 35 - 38   2009年1月

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)  

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  • ハロゲン電球におけるタングステン輸送現象の解析のための熱流体-化学平衡複合モデル 査読

    別所誠, 大河正志

    照明学会誌93 ( 11 ) 814 - 826   2009年

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.2150/jieij.93.814

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  • Oscillation frequency stabilization of a semiconductor laser by an indirect modulation method using the Faraday effect

    Akira Sato, Shinya Maehara, Tomoyuki Uehara, Hideaki Arai, Takashi Sato, Tadashi Tamura, Masashi Ohkawa, Seiji Kawamura

    PHYSICS AND SIMULATION OF OPTOELECTRONIC DEVICES XVII7211   72110A   2009年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:SPIE-INT SOC OPTICAL ENGINEERING  

    Scientists throughout the world are seeking to enhance the capabilities of satellite-to-satellite tracking laser interferometer-based optical systems used to measure the alterations in earth's gravitational field that indicate critical changes in the environment. These systems must be able to measure infinitesimal fluctuations in the relative velocities of two satellites, using a light source that oscillates at a level of frequency stability rated better than 10-13 in the square root of the Allan variance. In our experiments, semiconductor laser frequency stabilization that typically requires a brief direct modulation of the laser injection current to obtain an error signal, was accomplished using the Faraday effect of Rb absorption lines. This effectively modulates the reference frequency of the stabilization system, i.e., the Rb absorption line, by modulating the magnetic field applied to the Rb absorption cell, instead of the oscillation frequency of the laser diode. Most recently, we used the Faraday method, in conjunction with a precision temperature controller. For present purposes, we also use the PEAK method, to obtain the most accurate signal possible, comparing it with saturated absorption spectroscopic readings, to determine the noise-source.

    DOI: 10.1117/12.808803

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  • 熱流体-化学平衡複合モデルによるハロゲン電球タングステン輸送現象の検証 査読

    別所誠, 大河正志

    照明学会誌93 ( 11 ) 827 - 837   2009年

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.2150/jieij.93.827

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  • 光導波型圧力センサにおける共振周波数のダイヤフラムサイズ依存性 査読

    中島瑞季, 新國広幸, 大河正志, 佐藤孝

    電気学会論文誌E129 ( 10 ) 357 - 362   2009年

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.1541/ieejsmas.129.357

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  • Sensitivity dependences on side length and aspect ratio of a diaphragm in a glass-based guided-wave optical pressure sensor 査読

    Hiroyuki Nikkuni, Yu Watanabe, Masashi Ohkawa, Takashi Sato

    Optics Express16 ( 19 ) 15024 - 15033   2008年9月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Optical Society of America (OSA)  

    According to our previous theoretical study, sensor sensitivity is proportional to the cube of the side length of the diaphragm in a guided-wave optical pressure sensor consisting of a glass diaphragm and a single-mode waveguide on the diaphragm. Also, to obtain higher sensitivity, an aspect ratio of the diaphragm should be approximately 1 for two waveguide positions: the center and the edge of the diaphragm. In this study, sensitivity dependences on side length and aspect ratio of the diaphragm were experimentally examined. The obtained experimental results strongly supported the theoretical predictions. © 2008 Optical Society of America.

    DOI: 10.1364/OE.16.015024

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  • Resonance frequency of diaphragm in glass-based guided-wave optical pressure sensor

    Hiroyuki Nikkuni, Mizuki Nakajima, Masashi Ohkawa, Takashi Sato

    Techinical Digest of the 14th Microoptics Conference   P-71   2008年9月

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  • Characteristics of a guided-wave optical microphone with a micromachined diaphragm

    Noriyuki Watanabe, Hiroyuki Nikkuni, Masashi Ohkawa, Takashi Sato

    Technical Digest of the 14th Microoptics Conference   P-70   2008年9月

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)  

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  • Feasibility of a silicon-based guided-wave optical microphone

    Masashi Ohkawa, Manabu Hayashi, Hiroyuki Nikkuni, Noriyuki Watanabe, Takashi Sato

    ◦Integrated Photonics and Nanophotonics Research and Applications (IPNRA) 2008   JMB34   2008年7月

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  • Sensitivity dependence with respect to diaphragm thickness in guided-wave optical pressure sensor based on elasto-optic effect 査読

    Hiroyuki Nikkuni, Yu Watanabe, Masashi Ohkawa, Takashi Sato

    OPTICAL ENGINEERING47 ( 4 ) 044402   2008年4月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:SPIE-SOC PHOTOPTICAL INSTRUMENTATION ENGINEERS  

    We experimentally investigated the relationship between sensitivity and diaphragm thickness in a glass-based guided-wave optical pressure sensor using intermodal interference between the fundamental TM-like and TE-like modes. The sensor consists of a rectangular diaphragm and a straight single-mode waveguide on the diaphragm. The sensitivity is theoretically known to be inversely proportional to the square of the diaphragm thickness. In this study, to examine this relationship, four sensors with diaphragm thicknesses of 0.30 mm, 0.22 mm, 0.20 mm, and 0.15 mm were fabricated. The area of the diaphragm was 10 mm x 10 mm. For the waveguide position nearest to the center of the diaphragm, the measured sensitivities almost agreed with the theoretical ones. (C) 2008 Society of Photo-Optical Instrumentation Engineers.

    DOI: 10.1117/1.2909669

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  • Frequency stabilization of semiconductor lasers for onboard interferometers using both Rb-saturated absorption profiles and double-optical feedback systems

    K. Nakano, S. Maehara, M. Yanagisawa, A. Sato, K. Doi, T. Sato, M. Ohkawa, T. Maruyama, S. Kawamura

    SPACE TELESCOPES AND INSTRUMENTATION 2008: OPTICAL, INFRARED, AND MILLIMETER, PTS 1 AND 27010   701047   2008年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:SPIE-INT SOC OPTICAL ENGINEERING  

    The precise interferometric systems employed in today's artificial satellites require semiconductor lasers of the highest caliber. To this end, efforts to stabilize their oscillation frequencies and narrow spectrum line-widths continue relentlessly. While a number of different approaches have been tested, none have provided overall, long-term stability. Most recently, we employed a Doppler-free absorption line of Rb atoms, with a precision temperature controller and an improved laser mount. In this instance, relative optical frequency stability rated 9.07 x 10(-13)<=sigma(2,tau)<= 7.54x10(-10), in averaging time for 0.01s <=tau <= 23s. By introducing an optical feedback, which narrows the laser's linewidth, we obtained improved frequency stability.

    DOI: 10.1117/12.788681

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  • Frequency stabilization of an external cavity diode laser - Countermeasures against atmospheric temperature variations

    Yuta Minabe, Kohei Doi, Takashi Sato, Takeo Maruyama, Masashi Ohkawa, Tsuneya Tsubokawa

    PHYSICS AND SIMULATION OF OPTOELECTRONIC DEVICES XVI6889   688918   2008年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:SPIE-INT SOC OPTICAL ENGINEERING  

    External cavity diode lasers (ECDL) are presently experiencing a surge in popularity, as laser light-sources for advanced optical measurement systems. While these devices normally require external optical-output controls, we simplified the setup, a bit, by adding a second external cavity. This technique boasts the added advantage of having a narrower oscillation-linewidth than would be achievable, using a single optical feedback. Because drive-current and atmospheric temperature directly impact the ECDL systems' oscillation frequency, during frequency stability checks, it was necessary, in this instance, to construct a slightly smaller ECDL system, which we mounted on a Super-Invar board, to minimize the influence of thermal expansion. Taking these and other aggressive and timely measures to prevent atmospheric temperature-related changes allowed us to achieve an improvement in oscillation-frequency stability, i.e., to obtain the square root of Allan variance sigma =2 x 10(-10), at averaging time tau = 10(-1).
    We introduced a vertical-cavity surface-emitting laser (VCSEL) to the setup, for the simple reason that its frequency is far less susceptible to changes in temperature, than other lasers of its type. And, because VCSELs are widely available, and the ECDL systems that use them improve frequency stability, we replaced the Fabry-Perot semiconductor laser with a VCSEL.

    DOI: 10.1117/12.761598

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  • Semiconductor laser frequency-stabilization; influence of multi-position temperature controls

    M. Yanagisawa, K. Nakano, S. Maehara, T. Sato, M. Ohkawa, T. Maruyama, S. Kawamura

    PHYSICS AND SIMULATION OF OPTOELECTRONIC DEVICES XVI6889   688917   2008年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:SPIE-INT SOC OPTICAL ENGINEERING  

    The precise interferometric systems employed in today's artificial satellites require semiconductor lasers of the highest callibur. But, one particularly large obstacle has stood in the way of their broad application; the stabilization of their oscillation frequencies. While a number of different approaches have been tested, none have provided overall, long-term stability. Most recently, we used a Doppler-free absorption line of Rb atoms with a precision temperature controller and an improved laser mount; in this instance, relative optical frequency stability rated 9.07x10(-13)<=sigma(2,tau)<= 7.54x10(-10), in averaging time for 0.01s <=tau <= 23s. Furthermore, we heated the Rb cell to up to 313K, in order to enhance the control signal and improve oscillation frequency stability.

    DOI: 10.1117/12.761595

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  • Frequency stabilization of a semiconductor laser using both Rb saturated absorption profiles and double optical feedback systems

    K. Nakano, S. Machara, M. Yanagisawa, K. Doi, T. Sato, M. Ohkawa, T. Maruyama, S. Kawamura

    ADVANCED MATERIALS AND DEVICES FOR SENSING AND IMAGING III6829   68290R   2008年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:SPIE-INT SOC OPTICAL ENGINEERING  

    The precise interferometric systems employed in today's artificial satellites require semiconductor lasers of the highest callibur. But, one particularly large obstacle has stood in the way of their broad application; the stabilization of their oscillation frequencies. While a number of different approaches have been tested, none have provided overall, long-term stability. Most recently, we used a Doppler-free absorption line of Rb atoms with a precision temperature controller and an improved laser mount; in this instance, relative optical frequency stability rated 9.07 x 10(-13) <=sigma(2,tau)<= 7.54 x 10(-10), in averaging time for 0.01s <=tau <= 23s. By introducing optical feedback, which narrows the laser's linewidth, we obtained improved frequency stability.

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  • Analytical discussion of semiconductor lasers for Gravitational-wave detection

    T. Uehara, A. Sato, T. Sato, M. Ohkawa, T. Maruyama, S. Kawamura

    ADVANCED MATERIALS AND DEVICES FOR SENSING AND IMAGING III6829   68291H   2008年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:SPIE-INT SOC OPTICAL ENGINEERING  

    The primary objective of the Deci-hertz Interferometer Gravitational Wave Observatory (DECIGO) mission is to detect and observe black holes' and galactic binaries' gravitational waves (GWs), at frequencies ranging from 10(-2) to 10(1) HZ. This low-frequency range is inaccessible to ground-based interferometers, due to unshieldable background noise, -and the fact that ground-based interferometers are limited to a few kilometers in length. Our research is focused on efforts to stabilize semiconductor-, Nd:YAG- and fiber- lasers, for use as GW detectors' optical sources. In present-day- and future detectors, frequency- and phase-noise may place certain limitations on sensitivity and stability. Our goals (shared with scientists around the world) are; first, to design robust experiments that will measure a variety of noises (- random-walk FM, flicker-FM, white FM, flicker PM and white PM), in order to verify existing models, and second, -to find ways to reduce sensitivity to spurious noise. Current models predict a variety of frequency- and phase-dependent noise slopes, but, a conclusive distinction between noise-models can only be made when the exact points at which the noises occurred are known. In order to increase the sensitivity of the experiment, the laser frequency is stabilized to an atomic-frequency-reference by a feedback-loop control system.

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  • Sensitivity dependence on waveguide position in silicon-based optical flow sensor

    Masafumi Adachi, Yusuke Kudo, Masashi Ohkawa, Takashi Sato

    Technical Digest of the 13th Microoptics Conference   2007年10月

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  • Sensitivity dependence with respect to diaphragm dimensions in a glass-based guided-wave optical pressure sensor

    Yu Watanabe, Hiroyuki Nikkuni, Masashi Ohkawa, Takashi Sato

    Technical Digest of the 13th Microoptics Conference   2007年10月

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  • Improvement of S/N ratio of a Glass-Based Guided-Wave Optical Microphone 査読

    Manabu Hayashi, Hiroyuki Nikkuni, Yoshiaki Mogi, Masashi Ohkawa, Seishi Sekine, Takashi Sato

    International Symposium on Fusion Technology   123 - 123   2007年1月

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    記述言語:英語   掲載種別:研究論文(その他学術会議資料等)  

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  • Laser diode frequency stabilization by means of optical feedback and the Faraday effect 査読

    T. Uehara, S. Maehara, T. Nimonji, T. Sato, M. Ohkawa, T. Maruyama, S. Kawamura

    International Symposium on Fusion Technology   58 - 58   2007年1月

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    記述言語:英語   掲載種別:研究論文(その他学術会議資料等)  

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  • Semiconductor laser frequency stabilization using satulated absorption spectroscopy system 査読

    K. Nakano, S. Maehara, M. Yanagisawa, Y. Sekiya, T. Sato, M. Ohkawa, T. Maruyama, S. Kawamura

    International Symposium on Fusion Technology   57 - 57   2007年1月

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  • Evaluation of frequency stability in compact double optical feedback laser diode systems 査読

    Kohei Doi, Yuta Minabe, Toshiya Kaizaka, Takashi Sato, Takeo Maruyama, Masashi Ohkawa, Tsuneya Tsubokawa

    International Symposium on Fusion Technology   59 - 59   2007年1月

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  • Improvement of the signal-to-noise ratio in a glass-based guided-wave optical microphone 査読

    Hiroyuki Nikkuni, Yoshiaki Mogi, Manabu Hayashi, Masashi Ohkawa, Seishi Sekine, Takashi Sato

    INTEGRATED OPTICS: DEVICES, MATERIALS, AND TECHNOLOGIES XI6475   647519   2007年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:SPIE-INT SOC OPTICAL ENGINEERING  

    In this study, the signal-to-noise ratio of a glass-based guided-wave optical microphone was successfully improved by both increasing sensitivity and reducing noise. The optical microphone has a square diaphragm as a pressure-sensitive structure and a straight single-mode waveguide across the diaphragm. Sensitivity of the microphone and resonance frequency of the diaphragm are dependent on the area and thickness of the diaphragm. In this study, in order to increase sensitivity, the diaphragm dimensions were enlarged from 16 mm x 16 mm x 0.15 mm in the previous study to 20 mm x 20 mm x 0.15 mm. According to theoretical calculations, the phase sensitivity and resonance frequency were 2.5 mrad/Pa and 3.4 kHz for a 20 mm x 20 mm x 0.15 mm diaphragm, respectively. The sensitivity was theoretically expected to be twice as high as that in the previous study. To reduce noise, a bandpass filter with passband from 300 Hz to 3 kHz was employed. After fabrication of the optical microphone, sound pressure, ranging from 100 to 122 dB-SPL, was applied to the microphone with a frequency of I kHz. The measured output of the optical microphone was almost proportional to the sound pressure, and the minimum detectable sound pressure level of the microphone was experimentally evaluated to be 100 dB-SPL.

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  • Rb-saturated-absorption-profile-based enhancement of semiconductor laser frequency stability 査読

    K. Nakano, S. Maehara, M. Yanagisawa, Y. Sekiya, T. Sato, M. Ohkawa, T. Maruyama, S. Kawamura

    PHYSICS AND SIMULATION OF OPTOELECTRONIC DEVICES XV6468   64680C   2007年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:SPIE-INT SOC OPTICAL ENGINEERING  

    Laser interferometers detect gravitational waves with a degree of accuracy and efficiency unimaginable even a few years ago. The semiconductor lasers that are the primary light source for these devices are small, lightweight, durable and energy-efficient. On the downside, the devices currently available are still marked by broad oscillation spectra, and heightened sensitivity to fluctuations in injection current and /or ambient temperature. By applying a small sine wave to the injection current, we modulate the oscillation frequency. This frequency-modulated beam is introduced to the Avalanche photo diode through the Rb cell in the saturated absorption optical setup. The resulting signal and a reference signal are detected simultaneously and combined, to produce an error signal, which, when fed back to the injection current, stabilizes the diode's oscillation frequency at 2.12x10(-12) <= sigma(2,tau)<= 5.88x10(-11) in the averaging time between 0.4s to 65s. An optical feedback method, which introduces the laser beam reflected by a mirror or a grating to the semiconductor laser itself, is reported to narrow oscillation linewidth and improve frequency stability. We are now combining these two techniques to further improve frequency stability.

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  • Laser diode frequency stabilization by means of optical feedback and the magneto-optical effect 査読

    T. Uehara, S. Maehara, T. Nimonji, T. Sato, M. Ohkawa, T. Maruyama, S. Kawamura

    PHYSICS AND SIMULATION OF OPTOELECTRONIC DEVICES XV6468   64680D   2007年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:SPIE-INT SOC OPTICAL ENGINEERING  

    A method of detecting gravitational-field variations using laser diodes is described. While the GRACE project is currently using the Doppler microwave system to measure the velocities of satellites flying in tandem, in the future, more advanced laser interferometry will be employed. It is hoped that we will be able to measure infinitesimal changes in their velocities, by using frequency-stabilized lasers rated at better than 10(-13) in the square root of the Allan variance (sigma) for Is < tau < 100s. As laser light sources, these devices will be notable for their compactness, energy efficiency, lightweight and high frequency-stability. This thesis describes the improved frequency stabilization obtained through the use of the magneto-optical effect of the Rb-D-2 absorption line, and the adaptation of the PEAK method, in order to obtain a precise control signal. The method allows us to modulate the reference frequency of the stabilization system (the absorption spectrum of the Rb-D-2 absorption line) by modulating the magnetic field applied to the Rb absorption cell, instead of the oscillation frequency of the laser diode. In so doing we are able to achieve a frequency stabilized laser diode (sigma = 9 x 10(-12)), while maintaining its linewidth, at an averaging time of 40s. In the next stage, we will test frequency-stabilized laser optical sources that are to be used in detecting and observing gravitational waves.

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  • Compact double optical feedback external-cavity diode laser system and its frequency stabilization 査読

    Kohei Doi, Yuta Minabe, Takashi Sato, Takeo Maruyama, Masashi Ohkawa, Tsuneya Tsubokawa

    PHYSICS AND SIMULATION OF OPTOELECTRONIC DEVICES XV6468   64680E   2007年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:SPIE-INT SOC OPTICAL ENGINEERING  

    External cavity diode laser (ECDL) systems are presently experiencing a surge in popularity as laser light-sources, in advanced optical communications- and measurement-systems. Because such systems require that their external reflectors be precisely controlled, to eliminate low frequency fluctuations (LFF) in optical output, we conducted experiments with a two-cavity version, which easily eliminated LFFs, as expected. The technique has the added advantage of a narrower oscillation-linewidth than would be achievable, using a single optical feedback. However, the ECDL's oscillation frequency is susceptible to the influences of the drive-current, as well as changes, both in the refractive index, and the overall length of the external reflector that results from fluctuations in atmospheric temperature. We made every effort to maintain the length of the ECDL cavity, while evaluating oscillation-frequency stability. We used a Super-Invar board as the platform for our compact ECDL system to minimize the influence of thermal expansion, because of its low expansion coefficient. We then compared the effect of atmospheric temperature variations between two experimental conditions, with the Super-invar board and without it, and finally took note of the improvement in performance, using the board.

    DOI: 10.1117/12.698961

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  • The Japanese space gravitational wave antenna - DECIGO 査読

    Seiji Kawamura, Takashi Nakamura, Masaki Ando, Naoki Seto, Kimio Tsubono, Kenji Numata, Ryuichi Takahashi, Shigeo Nagano, Takehiko Ishikawa, Mitsuru Musha, Ken-ichi Ueda, Takashi Sato, Mizuhiko Hosokawa, Kazuhiro Agatsuma, Tomotada Akutsu, Koh-suke Aoyanagi, Koji Arai, Akito Araya, Hideki Asada, Yoichi Aso, Takeshi Chiba, Toshikazu Ebisuzaki, Yoshiharu Eriguchi, Masa-Katsu Fujimoto, Mitsuhiro Fukushima, Toshifumi Futamase, Katsuhiko Ganzu, Tomohiro Harada, Tatsuaki Hashimoto, Kazuhiro Hayama, Wataru Hikida, Yoshiaki Himemoto, Hisashi Hirabayashi, Takashi Hiramatsu, Kiyotomo Ichiki, Takeshi Ikegami, Kaiki T. Inoue, Kunihito Ioka, Koji Ishidoshiro, Yousuke Itoh, Shogo Kamagasako, Nobuyuki Kanda, Nobuki Kawashima, Hiroyuki Kirihara, Kenta Kiuchi, Shiho Kobayashi, Kazunori Kohri, Yasufumi Kojima, Keiko Kokeyama, Yoshihide Kozai, Hideaki Kudoh, Hiroo Kunimori, Kazuaki Kuroda, Kei-ichi Maeda, Hideo Matsuhara, Yasushi Mino, Osamu Miyakawa, Shinji Miyoki, Hiromi Mizusawa, Toshiyuki Morisawa, Shinji Mukohyama, Isao Naito, Noriyasu Nakagawa, Kouji Nakamura, Hiroyuki Nakano, Atsushi Nishizawa, Yoshito Niwa, Choetsu Nozawa, Masatake Ohashi, Naoko Ohishi, Masashi Ohkawa, Akira Okutomi, Kenichi Oohara, Norichika Sago, Motoyuki Saijo, Masaaki Sakagami, Shihori Sakata, Misao Sasaki, Shuichi Sato, Masaru Shibata, Hisaaki Shinkai, Kentaro Somiya, Hajime Sotani, Naoshi Sugiyama, Hideyuki Tagoshi, Tadayuki Takahashi, Hirotaka Takahashi, Ryutaro Takahashi, Tadashi Takano, Takahiro Tanaka, Keisuke Taniguchi, Atsushi Taruya, Hiroyuki Tashiro, Masao Tokunari, Shinji Tsujikawa, Yoshiki Tsunesada, Kazuhiro Yamamoto, Toshitaka Yamazaki, Jun'ichi Yokoyama, Chul-Moon Yoo, Shijun Yoshida, Taizoh Yoshino

    CLASSICAL AND QUANTUM GRAVITY23 ( 8 ) S125 - S131   2006年4月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:IOP PUBLISHING LTD  

    DECi-hertz Interferometer Gravitational wave Observatory (DECIGO) is the future Japanese space gravitational wave antenna. It aims at detecting various kinds of gravitational waves between 1 mHz and 100 Hz frequently enough to open a new window of observation for gravitational wave astronomy. The preconceptual design of DECIGO consists of three drag-free satellites, 1000 km apart from each other, whose relative displacements are measured by a Fabry-Perot Michelson interferometer. We plan to launch DECIGO in 2024 after a long and intense development phase, including two pathfinder missions for verification of required technologies.

    DOI: 10.1088/0264-9381/23/8/S17

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  • Evaluation of frequency stability in double optical feedback ECDL systems - art. no. 61150O 査読

    Kohei Doi, Yurnie Kobayashi, Shinya Maehara, Takashi Sato, Takeo Maruyama, Masashi Ohkawa, Tsuneya Tsubokawa

    Physics and SImulation of Optoelectronic Devices XIV6115   O1150 - O1150   2006年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:SPIE-INT SOC OPTICAL ENGINEERING  

    External cavity diode laser (ECDL) systems are presently experiencing a surge in popularity as laser light-sources, in Z 4:1 advanced optical communications- and measurement-applications. Because such systems require that their external reflectors be precisely controlled, to eliminate low frequency fluctuations (LFF) in optical output, we conducted experiments with a two-cavity version of the ECDL system. This technique brings the added advantages of a narrower linewidth than would be achievable via a single optical feedback. However, the ECDL's oscillation frequency is susceptible to the influences of the driving current, changes in the refractive index, and changes in external-reflector length that result from fluctuations in atmospheric temperature. We made every effort to maintain the length of the ECDL cavity, while evaluating oscillation-frequency stability. We used a Super-Invar board as the platform for our ECDL system, in order to minimize the influence of thermal expansion. Moreover, our ECDL system combines an Rb cell within an external cavity; an arrangement designed to improve stability by restricting the LD frequency within both the external cavity mode and the Rb-saturated absorption spectrum. We used the square root of the Allan variance, when evaluating oscillation frequency stability, observing, in the process, that it improved stability by about one order of magnitude.

    DOI: 10.1117/12.645759

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  • Guided-wave optical pressure sensor with semi-closed space under the diaphragm: step response in relation to the area of a small hole of a semi-closed space 査読

    Kaoru Sato, Masashi Ohkawa, Seishi Sekine, Takashi Sato

    PHOTONIC APPLICATIONS FOR AEROSPACE, TRANSPORTATION, AND HARSH ENVIRONMENTS6379   637908-1 - 637908-8   2006年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:SPIE-INT SOC OPTICAL ENGINEERING  

    An original guided-wave optical pressure sensor, which has a semi-closed space with a small hole under a diaphragm, can be used even under high quasi-static pressure without sacrificing sensitivity, unlike conventional pressure sensors. Moreover, the sensor possesses characteristics of a high-pass filter, so that it responds to only the high-frequency components of pressure change. The cutoff frequency of the high-pass filter of the sensor property is a key factor in designing the sensor, and is acquired from the step response of the sensor. In a step-like change in ambient pressure, a pressure difference is induced on the diaphragm for a short while because the small hole restricts fluid flow between the semi-closed space and the surroundings. The reciprocal of the duration of the induced pressure difference corresponds to the cutoff frequency. In this study, the step response in relation to the cross-sectional area of the small hole was examined experimentally, and the measured durations were compared with the theoretical ones. In the experiment, the duration was approximately inversely proportional to the area of the small hole as theoretically predicted although the measured durations are larger by a factor of thousands than the calculated ones.

    DOI: 10.1117/12.685977

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  • Stability of holographic gratings recorded on photopolymer using different dyes 査読

    Keiichi Tsuchida, Masashi Ohkawa, Seishi Sekine

    PRACTICAL HOLOGRAPHY XX: MATERIALS AND APPLICATIONS6136   613610-1 - 613610-8   2006年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:SPIE-INT SOC OPTICAL ENGINEERING  

    In this study, stability of holographic gratings recorded in four photopolymer films with different dyes was experimentally examined. Also, dye concentration was optimized to get high diffraction efficiency. Each film contains triethanolamine and acrylamide in polyvinyl alcohol matrix, and one type of dye: eosin Y, methyl violet, rhodamine B or rose bengal. Dye concentrations were adjusted so that transmittances of the four films 60 mu m thick were approximately 94%. The photopolymer films were exposed by two intersecting beams of a YVO laser at 532 nm to form holographic grating with spatial frequency of 653 line/mm until the diffraction efficiency reached its maximum. The power of each recording beam was 10 mW, and its diameter was 2.25 mm each.
    Diffraction efficiency was measured using a YVO laser beam for the recorded films undergoing either 300 sec reconstruction or 5-day dark storage. The photopolymer film containing eosin Y showed the best stability both for a 300 sec reconstruction and for 5-day storage. Regarding optimization of dye concentration, the diffraction efficiencies of more than 60% were obtained when an amount of eosin Y is between 1 mg and 50 mg, which was solved in 9.1 % polyvinyl alcohol aqueous solution of 110 g.

    DOI: 10.1117/12.645913

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  • Frequency stabilization of laser diode light-sources in satellite-to-satellite laser interferometers - art. no. 611529 査読

    S. Maehara, Y. Kurosaki, T. Sato, M. Ohkawa, T. Maruyama, T. Yoshino, H. Kunimori, M. Hosokowa, H. Ito, Y. Li, S. Nagano, S. Kawamura

    Physics and SImulation of Optoelectronic Devices XIV6115   11529 - 11529   2006年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:SPIE-INT SOC OPTICAL ENGINEERING  

    The present work discusses methods of stabilizing the frequencies of commercially-available laser diodes. Laser diodes are generally compact and long-lived. The frequency stability, which makes them ideal for onboard laser interferometer light-sources, in applications such as the satellite-to-satellite tracking systems used to verify fluctuations in earth's gravity field, which, in turn, indicate other critical changes in the environment, is the key characteristic of this work. We used the devices typically operating at 780nm, and their frequencies can be stabilized using either of two systems; one, employing the Doppler-free absorption line of Rb atoms and another, using the Faraday effect of the Rb absorption line. In both cases, the use of the proper modulation frequency and amplitude improved frequency stability, overall, attaining 2.05 x 10(-12) and 2.73 x 10(-11), respectively, in the square root of the Allan variance, by measuring the beat-note between two independently-stabilized laser diodes.

    DOI: 10.1117/12.645751

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  • An investigation into changes observed in the oscillation characteristics of semiconductor lasers exposed to magnetic fields - art. no. 61150Z 査読

    T. Miyamoto, J. Chiba, T. Sato, M. Ohkawa, T. Maruyama

    Physics and SImulation of Optoelectronic Devices XIV6115   Z1150 - Z1150   2006年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:SPIE-INT SOC OPTICAL ENGINEERING  

    Semiconductor lasers' oscillation wavelengths respond to temperature-, injection current-, and magnetic field-fluctuations. As reported in the 1960's, the oscillation wavelength shortened, under magnetic fields stronger than 4T, at temperatures lower than 80K. However, when we exposed bulk-type semiconductor lasers oscillating at 780nm to relatively weak magnetic fields (less than 1.4T), at room temperature (300K), we observed that the oscillation wavelength shifted to the longer (lower frequency) side. In this work, we focused on the longer oscillation wavelength shift, the lower power side optical output-power shift, and the higher voltage side terminal voltage shift of a number of multi-quantum-well (MQW) laser diodes oscillating at 780nm, under the same experimental conditions as those used in our previous works. In discussions of these shift mechanisms, we consider how wavelength (frequency), optical output-power, and terminal voltage shifts are correlated. Because our new knowledge arrows us to employ mechanisms completely different from those used in studies dating as far back as the 1960's, we have introduced one whereby the shifts observed in our experiments result from temperature rises and longitudinal magneto-resistance effects. Also discussed, are the results of experiments conducted near the threshold current.

    DOI: 10.1117/12.645485

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  • Frequency stabilization of a semiconductor laser using the Rb saturated absorption spectroscopy - art. no. 61150P 査読

    Y. Ohta, S. Maehara, K. Hasebe, Y. Kurosaki, T. Sato, M. Ohkawa, T. Maruyama, T. Tsubokawa

    Physics and SImulation of Optoelectronic Devices XIV6115   P1150 - P1150   2006年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:SPIE-INT SOC OPTICAL ENGINEERING  

    We report on the stabilization of a semiconductor laser's frequency, using Rb absorption lines. In order to improve overall frequency stability within our system, we adjusted the setup used in Rb- saturated absorption spectroscopy, and optimized modulation parameters such as modulation - frequency and -width, to more accurately detect the error signal. When we stabilized laser frequency using a Doppler-free absorption line of Rb atoms, a time-constant of 0.01sec, and a modulation frequency of 7.77kHz, relative optical frequency stability of 2.12x10(-12)<=sigma(2,tau)<= 5.88x10(-11) was achieved, in averaging time for 0.04s <=tau <= 65s.

    DOI: 10.1117/12.645726

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  • Evaluation of frequency stability in double optical feedback ECDL systems 査読

    Kohei Doi, Yumie Kobayashi, Shinya Maehara, Takashi Sato, Takeo Maruyama, Masashi Ohkawa, Tsuneya Tsubokawa

    Proceedings of SPIE - The International Society for Optical Engineering6115   70 - 76   2006年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)  

    External cavity diode laser (ECDL) systems are presently experiencing a surge in popularity as laser light-sources, in advanced optical communications- and measurement-applications. Because such systems require that their external reflectors be precisely controlled, to eliminate low frequency fluctuations (LFF) in optical output, we conducted experiments with a two-cavity version of the ECDL system. This technique brings the added advantages of a narrower linewidth than would be achievable via a single optical feedback. However, the ECDL's oscillation frequency is susceptible to the influences of the driving current, changes in the refractive index, and changes in external-reflector length that result from fluctuations in atmospheric temperature. We made every effort to maintain the length of the ECDL cavity, while evaluating oscillation-frequency stability. We used a Super-Invar board as the platform for our ECDL system, in order to minimize the influence of thermal expansion. Moreover, our ECDL system combines an Rb cell within an external cavity
    an arrangement designed to improve stability by restricting the LD frequency within both the external cavity mode and the Rb-saturated absorption spectrum. We used the square root of the Allan variance, when evaluating oscillation frequency stability, observing, in the process, that it improved stability by about one order of magnitude.

    DOI: 10.1117/12.645759

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  • Development of a simulator of a satellite-to-satellite interferometer for determination of the Earth's gravity field 査読

    S Nagano, M Hosokawa, H Kunimori, T Yoshino, S Kawamura, M Ohkawa, T Sato

    REVIEW OF SCIENTIFIC INSTRUMENTS76 ( 12 ) 124501-1 - 124501-10   2005年12月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:AMER INST PHYSICS  

    A satellite-to-satellite laser interferometer is essential for a future gravity-field mission to improve the accuracy and spatial resolution of the Earth's gravity model. We have designed a ground-based simulator of a satellite-to-satellite interferometer, which aims to evaluate instrument error reflecting on the accuracy of the gravity-field retrieval and achieve the essential technologies required to measure the intersatellite range rate. The developed simulator was successfully operated with a range-rate sensitivity of 40 nm/s/<radical><radicand>Hz</radicand></radical> in the measurement band of 10(-2)-1 Hz. From a primary demonstration, it was confirmed to be available for experimental simulation of the satellite-to-satellite interferometer in the laboratory. The simulator will be a powerful tool for establishing guidelines for the development of future gravity missions. (c) 2005 American Institute of Physics.

    DOI: 10.1063/1.2140280

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  • Silicon-based guided-wave optical flow sensor based on Bernoulli's Theorem 査読

    Yusuke Ohara, Masanori Tsuchiya, Masashi Ohkawa, Seishi Sekine, Takashi Sato

    6th Japan-Finland Joint Symposium on Optics in Engineering   77 - 78   2005年9月

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    記述言語:英語   掲載種別:研究論文(その他学術会議資料等)  

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  • Guided-wave optical pressure sensor responding only to changing pressure 査読

    Yoshisumi Endo, Masashi Ohkawa, Seishi Sekine, Takashi Sato

    Progress in Biomedical Optics and Imaging - Proceedings of SPIE5728   309 - 316   2005年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)  

    In this paper, an original guided-wave optical pressure sensor that responds only to rapid pressure change is described. The proposed sensor is based on a conventional guided-wave optical pressure sensor using intermodal interference, with an added semi-closed space with a small hole under the bottom side of the diaphragm. By the addition of this semi-closed space, the sensor, unlike conventional sensors, can withstand high static pressure. When there is a sudden change in ambient pressure, pressure within the semi-closed space cannot quickly adjust due to the small hole that restricts fluid flow. So, pressure difference is induced on the diaphragm for a short while. Thus, the sensor shows a response only to changes in pressure, not to static pressure. We examined the step response of the sensor, that is, the output characteristics for sudden pressure change. The diaphragm dimensions of the fabricated sensor were 14 mm×14 mm×0.22 mm. Also, the volume of the semi-closed space was 14 mm×14 mm×1.8 mm, and the sectional area of the small hole was 93 μm×25 μm. In this experiment, the pressure in a 30 cm×28 cm×30 cm closed box, in which the fabricated sensor was placed, was suddenly increased by 0.78 kPa. Due to the pressure change, the output intensity decreased by approximately 20% of the initial intensity level. Approximately 1.4 sec after the step-like change in pressure, output intensity returned to the initial level.

    DOI: 10.1117/12.588457

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  • Optical microphone using a silicon-based guided-wave optical pressure sensor 査読

    H Nikkuni, S Dokko, M Ohkawa, S Sekine, T Sato

    Integrated Optics: Devices, Materials, and Technologies IX5728   317 - 324   2005年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:SPIE-INT SOC OPTICAL ENGINEERING  

    In this paper, an optical microphone using a silicon-based guided-wave optical pressure sensor as an opto-mechanical transducer is reported. The pressure sensor consists of a rectangular diaphragm and a straight waveguide on the diaphragm. The sensitivity of the sensor and the resonance frequency of the diaphragm are important factors to determine the characteristics of the microphone, and depend on the diaphragm dimensions. In this study, to examine a feasibility of the proposed optical microphone, the target values of phase sensitivity and resonance frequency were set at 1.6 mrad/Pa and 7 kHz, respectively. By design considerations, the diaphragm dimensions were determined to be 7 mm x 7 mm x 23 mu m. After fabrication of the optical microphone, sound pressure from 5 to 25 Pa, with a frequency of 1 kHz, was applied to the fabricated microphone with a 7 mmx 7 mmx 27 gm diaphragm. During measurement, a lock-in detection was taken because the fabricated pressure sensor had an unexpected low sensitivity, which resulted in an extremely low S/N ratio. The measured output voltage from the lock-in amplifier was proportional to the sound pressure as expected although the lock-in detection is not practical for the microphone.

    DOI: 10.1117/12.588456

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  • Frequency stabilization of a semiconductor laser using the spectrum of a Fabry-Perot etalon controlled by the Rb absorption line 査読

    Y Kurosaki, S Maehara, K Hasebe, Y Ohta, T Sato, M Ohkawa, T Maruyama, T Tsubokawa

    Nonlinear Frequency Generation and Conversion: Materials, Devices, and Applications IV5710   73 - 82   2005年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:SPIE-INT SOC OPTICAL ENGINEERING  

    We report on the stabilization of a semiconductor laser's frequency, using spectra-controlled etalon. As the spectra of an etalon are controlled by, one of the Rb absorption lines.. they provide highly stable reference frequencies in a broad frequency range. When we adapted the PEAK method to the etalon's spectra and used a Doppler-free absorption line of Rb atoms as the control signal for the newest model of our system, relative optical frequency stability of 2.91 x 10(-11) <= sigma(2,tau) <= 3.72 x 10(-10) was achieved in averaging time for 0.04 <= tau <= 100s.

    DOI: 10.1117/12.589743

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  • Measurement of Complex Refractive Index of Tungsten by Using Ellipsometry — Study of the Accuracy of Ellipsometer — 査読

    Ayumu Sato, Seishi Sekine, Masashi Ohkawa

    Journal of Light and Visual Environment29 ( 2 ) 55 - 61   2005年

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    Tungsten microcavity light sources and tungsten cluster light sources have interested us as light sources for next-generation having high luminous efficacy and long lifetime. The complex refractive index of tungsten requires the operating temperatures from 2000 K to 6500 K to evaluate the luminous efficacy and lifetime. Little is, known however, about the complex index of tungsten at such high temperatures. Since ellipsometry has a non-contact measurement technique, the complex refractive index of any metal can be measured even under extremely high temperature with high accuracy. We consider that ellipsometry is an effective measuring method. We thus designed and fabricated the ellipsometer to measure the complex refractive index of tungsten at room temperature. As the result, we established the ellipsometer improved from measurement of the complex refractive index of tungsten from 2000 K to 6500 K. In this paper, we report on the problems to measure the complex refractive index of tungsten using the ellipsometry, and the achieved accuracy of measurement. KEYWORDS: microcavity light source, cluster light source, tungsten, complex refractive index, ellipsometry. © 2005, The Illuminating Engineering Institute of Japan. All rights reserved.

    DOI: 10.2150/jlve.29.55

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  • Evaluation of Complex Refractive Index of Metal Clusters by Scattering Ellipsometry 査読

    Ayumu Sato, Yasunari Harada, Seishi Sekine, Masashi Ohkawa

    IEEJ Transactions on Fundamentals and Materials125 ( 5 ) 461 - 465   2005年

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    A scattering ellipsometry is a newly developed method to measure a complex refractive index of metal clusters at a high temperature region. The complex refractive index is required to determine a luminous efficacy, which is one of the most important factors to develop lamps, of cluster lamps. In this study, we built a scattering ellipsometer, and considered its accuracy of measurement through evaluations of the complex refractive index of gold particles at room temperature. In measurement, a Nd: YAG laser of 532 nm was used as the light source. The measured complex refractive index of gold particles was 0.31 in real part and 1.75 in imaginary part. A repeatable accuracy was evaluated 0.01 in real part and 0.02 in imaginary part from a standard deviation in measuring the complex refractive index 10 times in the same condition. Also, the size parameter of gold particles was 1.71, and its repeatable accuracy was 0.02. Such accuracy is sufficient to estimate characteristics of the cluster lamps, such as the spectral radiant flux, the luminous efficacy and so on. © 2005, The Institute of Electrical Engineers of Japan. All rights reserved.

    DOI: 10.1541/ieejfms.125.461

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  • Guided-wave optical pressure sensor responding only to changing pressure 査読

    Y Endo, M Ohkawa, S Sekine, T Sato

    Integrated Optics: Devices, Materials, and Technologies IX5728   309 - 316   2005年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:SPIE-INT SOC OPTICAL ENGINEERING  

    In this paper, an original guided-wave optical pressure sensor that responds only to rapid pressure change is described. The proposed sensor is based on a conventional guided-wave optical pressure sensor using intermodal interference, with an added semi-closed space with a small hole under the bottom side of the diaphragm. By the addition of this semi-closed space, the sensor, unlike conventional sensors, can withstand high static pressure. When there is a sudden change in ambient pressure, pressure within the semi-closed space cannot quickly adjust due to the small hole that restricts fluid flow. So, pressure difference is induced on the diaphragm for a short while. Thus, the sensor shows a response only to changes in pressure, not to static pressure. We examined the step response of the sensor, that is, the output characteristics for sudden pressure change. The diaphragm dimensions of the fabricated sensor were 14 mmx14 mmx0.22 mm. Also, the volume of the semi-closed space was 14 mmx14 mmx1.8 mm, and the sectional area of the small hole was 93 mu mx25 mu m. In this experiment, the pressure in a 30 cmx28 cmx30 cm closed box, in which the fabricated sensor was placed, was suddenly increased by 0.78 kPa. Due to the pressure change, the output intensity decreased by approximately 20 % of the initial intensity level. Approximately 1.4 sec after the step-like change in pressure, output intensity returned to the initial level.

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  • Holographic characteristics of two different films using methyl violet dyes in polyvinyl alcohol matrices 査読

    K Tsuchida, M Ohkawa, S Sekine

    Practical Holography XIX: Materials and Applications5742 ( 1 ) 250 - 258   2005年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:SPIE-INT SOC OPTICAL ENGINEERING  

    Holographic characteristics of two different films using methyl violet dyes in polyvinyl alcohol matrices are reported. One of the films, Film A, contains only methyl violet in the matrix. The other film, Film B, contains methyl violet, triethanolamine and acrylamide in the matrix. Diffraction efficiencies of the two films were measured and compared. Mechanisms of holographic recording and the functions of the dyes are discussed. The films were 8 pm thick.. Holographic gratings were recorded in the films by two intersecting YVO laser beams at 532 nm. The recording intensity of each beam was 25 mW, 50 mW and 100 mW, and the beam diameter was 2.25 mm. The spatial frequency of the grating was 653 line/mm. During recording, intensity of the diffracted light was simultaneously measured using a He-Ne laser at 633 nm. Regarding Film A, diffraction efficiency reaches a peak at a specific exposure time. This means that holographic grating grows according to exposure time in low exposure, but vanishes when over-exposed. In bright regions of the interference fringe on the film, the dyes are bleached. Changes of absorption and refractive index due to bleaching would result in the holographic grating. Regarding Film B, the diffraction efficiency was saturated in high exposure, and the maximum diffraction efficiency was not strongly dependent on the concentration of methyl violet. In the bright regions of the interference fringe on the film, excited methyl violet and triethanolamine cause polymerization of acrylamide. Changes in the refractive index due to the polymerization build the holographic grating.

    DOI: 10.1117/12.588487

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  • Holographic characteristics of two different films using methyl violet dyes in polyvinyl alcohol matrices 査読

    K Tsuchida, M Ohkawa, S Sekine

    Practical Holography XIX: Materials and Applications5742   250 - 258   2005年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:SPIE-INT SOC OPTICAL ENGINEERING  

    Holographic characteristics of two different films using methyl violet dyes in polyvinyl alcohol matrices are reported. One of the films, Film A, contains only methyl violet in the matrix. The other film, Film B, contains methyl violet, triethanolamine and acrylamide in the matrix. Diffraction efficiencies of the two films were measured and compared. Mechanisms of holographic recording and the functions of the dyes are discussed. The films were 8 pm thick.. Holographic gratings were recorded in the films by two intersecting YVO laser beams at 532 nm. The recording intensity of each beam was 25 mW, 50 mW and 100 mW, and the beam diameter was 2.25 mm. The spatial frequency of the grating was 653 line/mm. During recording, intensity of the diffracted light was simultaneously measured using a He-Ne laser at 633 nm. Regarding Film A, diffraction efficiency reaches a peak at a specific exposure time. This means that holographic grating grows according to exposure time in low exposure, but vanishes when over-exposed. In bright regions of the interference fringe on the film, the dyes are bleached. Changes of absorption and refractive index due to bleaching would result in the holographic grating. Regarding Film B, the diffraction efficiency was saturated in high exposure, and the maximum diffraction efficiency was not strongly dependent on the concentration of methyl violet. In the bright regions of the interference fringe on the film, excited methyl violet and triethanolamine cause polymerization of acrylamide. Changes in the refractive index due to the polymerization build the holographic grating.

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  • Magnetic fields' effect on semiconductor lasers' characteristics 査読

    Y Seto, T Miyamoto, T Sato, M Ohkawa, T Maruyama

    Physics and Simulation of Optoelectronic Devices XIII5722   90 - 97   2005年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:SPIE-INT SOC OPTICAL ENGINEERING  

    Semiconductor lasers' oscillation wavelengths respond to temperature- and magnetic field-fluctuations. As reported in the 1960's, these wavelengths shortened, at lower than 80K, under a magnetic field larger than 4T. This phenomenon attracted our attention, during preliminary experiments, because, when we exposed bulk-type semiconductor lasers oscillating at 780nm to relatively weak magnetic fields (less than 1.4T), at room temperature (300K), we observed that the oscillation wavelength shifted to the longer (lower frequency) side. For this work, we focused on the longer oscillation wavelength shift, the lower power side optical output-power shift, and the higher voltage side terminal voltage shift of a number of multi-quantum-well (MQW) laser diodes oscillating at 780nm, under the same experimental conditions as those used in our previous works. In discussions of these shift mechanisms, we consider how wavelength (frequency), optical output-power, and terminal voltage shifts are correlated. Our expanded knowledge base has forced us to employ mechanisms completely different from those used in studies dating as far back as the 1960's. We are now introducing a mechanism in which temperature rise and the longitudinal magneto-resistance effect cause the shifts observed in our experiments.

    DOI: 10.1117/12.589744

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  • Oscillation frequency stabilization of a semiconductor laser using the Faraday effect of Rb absorption lines and the double optical feedback 査読

    H Kobayashi, T Nimonji, S Maehara, T Sato, M Ohkawa, T Maruyama, T Yoshino, H Kunimori, M Hosokawa, H Ito, Y Li, S Nagano, S Kawamura

    Nonlinear Frequency Generation and Conversion: Materials, Devices, and Applications IV5710   83 - 90   2005年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:SPIE-INT SOC OPTICAL ENGINEERING  

    Currently in the initial stages of development, the endeavor aims to use satellite-to-satellite tracking laser interferometer-based optical technique, to document fluctuations in earth's gravitational field indicating other critical changes in the environment. This system must be able to measure infinitesimal changes in the relative velocity of the two satellites, using a laser light source, which oscillates at frequency stability better than 10(-13) in the square root of the Allan variance. We have stabilized the laser's oscillation frequency using the Faraday effect of Rb absorption lines. This method modulates the reference frequency of the stabilization system by modulating the magnetic field applied to the Rb, absorption cell, instead of the oscillation frequency of the laser diode. Furthermore, we have adapted the "double optical feedback" to the laser diode for narrowing its oscillation spectrum and improving its frequency stability. In recent years, a "femtosecond optical comb generator" has been developed as a new reference frequency source for absolute frequency measurement. This optical comb generator is controlled by the microwave frequency standards systems and provides stability of 4 x 10(-13) at an averaging time of 1s and at the order of 10(-15) at 1000s averaging time. We have measured the frequency stability of our system using the optical comb. We obtained the best spectrum narrowing effect using two gratings as external reflectors in the double optical feedback setup. The obtained results were 6.269 x 10(-11) <= sigma <= 1.516 x 10(-10)(24.11kHz <= f <= 58.31kHz) from Is to 39s in the averaging time.

    DOI: 10.1117/12.590396

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  • Feasibility of guided-wave optical microphone based on elasto-optic effect 査読

    Hiroyuki Nikkuni, Masashi Ohkawa, Seishi Sekine, Takashi Sato

    Proceedings of SPIE - The International Society for Optical Engineering6049   56 - 63   2005年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)  

    In this paper, the feasibility of a glass-based guided-wave optical microphone is described. The optical microphone consists of a rectangular diaphragm and a straight waveguide on the diaphragm. The sensitivity of the microphone and the resonance frequency of the diaphragm are dependent on the diaphragm dimensions. In this study, to confirm operation of the proposed optical microphone, the target values for phase sensitivity and resonance frequency were set at 1.3 mrad/Pa and 5 kHz, respectively. By design considerations, the diaphragm dimensions were determined to be 16 mm× 16 mm×0.15 mm. After fabrication, a sound wave of 1 kHz and 25 Pa, corresponding to 122 dB-SPL (sound pressure level), was applied to the microphone. In the experiment, the intensity-modulated output with the same frequency as the applied sound wave was obtained, but the observed output was unexpectedly caused by misalignment of the optical components due to mechanical vibration. The estimated output signal by the normal operation of the microphone for a sound pressure of 25 Pa was 1/10 - 1/100 of the noise level, according to the measured output characteristic to static pressure. In order to detect normal speech ranging from 55 to 65 dB-SPL, the S/N ratio should be improved by a factor of more than 104.

    DOI: 10.1117/12.649176

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  • Optical microphone using a silicon-based guided-wave optical pressure sensor 査読

    Hiroyuki Nikkuni, Shuuichi Dokko, Masashi Ohkawa, Seishi Sekine, Takashi Sato

    Progress in Biomedical Optics and Imaging - Proceedings of SPIE5728   317 - 324   2005年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)  

    In this paper, an optical microphone using a silicon-based guided-wave optical pressure sensor as an opto-mechanical transducer is reported. The pressure sensor consists of a rectangular diaphragm and a straight waveguide on the diaphragm. The sensitivity of the sensor and the resonance frequency of the diaphragm are important factors to determine the characteristics of the microphone, and depend on the diaphragm dimensions. In this study, to examine a feasibility of the proposed optical microphone, the target values of phase sensitivity and resonance frequency were set at 1.6 mrad/Pa and 7 kHz, respectively. By design considerations, the diaphragm dimensions were determined to be 7 mm× 7 mm× 23 μm. After fabrication of the optical microphone, sound pressure from 5 to 25 Pa, with a frequency of 1 kHz, was applied to the fabricated microphone with a 7 mm× 7 mm× 27 μm diaphragm. During measurement, a lock-in detection was taken because the fabricated pressure sensor had an unexpected low sensitivity, which resulted in an extremely low S/N ratio. The measured output voltage from the lock-in amplifier was proportional to the sound pressure as expected although the lock-in detection is not practical for the microphone.

    DOI: 10.1117/12.588456

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  • Evaluation of oscillation frequency stability of a diode laser using a fs laser optical comb 査読

    H Kobayashi, T Nimonji, A Sawamura, T Sato, M Ohkawa, T Maruyama, T Yoshino, H Kunimori, M Hosokawa, H Ito, Y Li, S Nagano, S Kawamura

    ULTRAFAST PHENOMENA XIV79   849 - 851   2005年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:SPRINGER-VERLAG BERLIN  

    We have stabilized the oscillation frequency of a diode laser using the Faraday effect of Rb absorption lines. The stabilized laser frequency was measured by means of a femtosecond mode-locked pulse laser optical comb generator.

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  • タングステンクラスター光源のハロゲン化物に因る放射特性の検討 査読

    佐藤歩, 保坂和幸, 久保博樹, 関根征士, 大河正志

    照明学会誌88 ( 5 ) 281 - 287   2004年12月

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.2150/jieij.88.281

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  • Displacement measuring technique for satellite-to-satellite laser interferometer to determine Earth's gravity field 査読

    S Nagano, T Yoshino, H Kunimori, M Hosokawa, S Kawamura, T Sato, M Ohkawa

    MEASUREMENT SCIENCE AND TECHNOLOGY15 ( 12 ) 2406 - 2411   2004年12月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:IOP PUBLISHING LTD  

    We present a new displacement measuring technique with simplicity, robustness, high sensitivity and wide measurement range. A set of a frequency shifter and a voltage-frequency converter is used to lock a homodyne interferometer on the half-bright fringe by eliminating the Doppler fringe resulting from mirror motion. The mirror displacement is directly retrieved from the feedback signal of a fringe control loop. By developing a table-top interferometer, we successfully demonstrated signal recovery without significant degradation. The achieved displacement sensitivity and measurement range of the interferometer were 24 nm Hz(-1/2) and 1.3 mm at a Fourier frequency of 0.1 Hz, respectively. This technique was found to have a potential for application to precise displacement measurements. It is, in particular, suitable for a satellite-to-satellite laser interferometer to determine Earth's gravity field.

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  • Evaluation of the Artificial Neural Network for Color Discrimination-Discrimination of Non-learned Colors- 査読

    Yasuko Tayagaki, Satoko Sekiya, Seishi Sekine, Masashi Ohkawa

    Journal of Light and Visual Environment28 ( 2 ) 101 - 103   2004年9月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    Our research purpose is to build an artificial neural network with an excellent color discrimination capability like human being on a computer. In this study, we built the network, which was trained to learn 10 colors with different hues in the Munsell color system. Then, we examined the response of the trained network when the network was interrogated about 10 non-learned colors. The network showed a good color discrimination capability, close to that of human being. © 2004, The Illuminating Engineering Institute of Japan. All rights reserved.

    DOI: 10.2150/jlve.28.101

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  • Holographic characteristics of two different films using methyl violet dyes in polyvinyl alchohol matrices 査読

    Keiichi Tuchida, Masashi Ohkawa, Seishi Sekine

    EM-NANO 2004   124 - 124   2004年6月

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    記述言語:英語   掲載種別:研究論文(その他学術会議資料等)  

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  • Guided-wave optical pressure sensor with sensitivity for sudden pressure change only 査読

    Yoshisumi Endo, Masashi Ohkawa, Seishi Sekine, Takashi Sato

    EM-NANO 2004   228 - 228   2004年6月

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    記述言語:英語   掲載種別:研究論文(その他学術会議資料等)  

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  • Development of a light source in a satellite-to-satellite laser interferometer for the precise measurement of their relative velocity 査読

    Toshiya Nimonji, shinya Maehara, Hiromichi Kobayashi, Takeshi Sato, Masashi Ohkawa, Takeo Maruyama

    EM-NANO 2004   224 - 224   2004年6月

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  • Ground simulator for future satellite gravity mission by inter-satellite laser interferometer 査読

    Taizoh Yoshino, Shigeo Nagano, Hiroo Kunimori, Mizuhiko Hosokawa, Seiji Kawamura, Takashi Sato, Masashi Ohkawa

    1st European Geosciences Union(EGU) General Assembly1   P0823   2004年4月

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    記述言語:英語   掲載種別:研究論文(その他学術会議資料等)  

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  • Measurement of Complex Refractive Index of Tungsten by Using Ellipsometry 査読

    Ayumu Sato, Seishi Sekine, Masashi Ohkawa

    IEEJ Transactions on Fundamentals and Materials124 ( 2 ) 114 - 119   2004年

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    In development of tungsten microcavity illuminants and tungsten cluster illuminants, the Complex Reractive Index of tungsten at the operating temperature of 2000–6000 K is necessary to evaluate their luminous efficacy and lifetime. Little is, however, known about the complex index of tungsten in such a high temperature region. In this study, we have determined the complex index of tungsten using an ellipsometer at room temperature. In measurement, a He-Ne laser of 633 nm and a Nd:YAG laser of 532 nm were used as the light sources. The measured complex index of tungsten was 2.0 to 3.0 in real part and 2.5 to 3.0 in imaginary part at 633 nm. Also, the corresponding components at 532 nm were 1.8 to 2.8 and 2.4 to 2.8. Repeatable accuracy was estimated about 1% in measuring the complex index repeatedly at the same point on individual tungsten plates. It was, however, found that the measured complex index was linearly proportional to the reflectivity. This dependence is attributed to surface conditions such as oxidation and roughness on a microscopic scale. © 2004, The Institute of Electrical Engineers of Japan. All rights reserved.

    DOI: 10.1541/ieejfms.124.114

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  • New frequency stabilization method of a semiconductor laser using the Faraday effect of the Rb-D2 absorption line 査読

    Toshiya Nimonji, Shin-Ichi Ito, Akihiko Sawamura, Takashi Sato, Masashi Ohkawa, Takeo Maruyama

    Japanese Journal of Applied Physics, Part 1: Regular Papers and Short Notes and Review Papers43 ( 5 A ) 2504 - 2509   2004年

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Japan Society of Applied Physics  

    We have applied a precise amount of electrical feedback into laser injection current to stabilize the oscillation frequency of a semiconductor laser. This feedback method usually requires a small direct modulation to the laser injection current to obtain an error signal. This broadens the oscillation width of the laser diode, but certain applications, such as those related to coherent optical communications and measurements, require a narrower oscillation linewidth. Thus, we have attempted to obtain the error signal and stabilize the laser oscillation frequency in a narrower oscillation linewidth using the Faraday effect of the Rb absorption line. Our next task for the Faraday-effect-based method involves frequency stabilization, which we accomplish using a large frequency discrimination gain Gd. By incorporating our "PEAK" circuit, which utilizes the envelope detection method to determine the switching points between two different absorption signals, we increase Gd in our improved PEAK methods.

    DOI: 10.1143/JJAP.43.2504

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  • Oscillation frequency stabilization of a diode laser for the laser interferometer in a satellite-to-satellite tracking system 査読

    S Maehara, H Kobayashi, T Sato, M Ohkawa, T Maruyama, T Yoshino, H Kunimori, M Hosokowa, H Ito, Y Li, S Nagano, S Kawamura

    SEMICONDUCTOR LASERS AND APPLICATIONS II5628   113 - 120   2004年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:SPIE-INT SOC OPTICAL ENGINEERING  

    Currently in the initial stages of development, the endeavor aims to use satellite-to-satellite tracking laser interferometer-based optical technique, to document fluctuations in earth's gravitational field indicating other critical changes in the environment. This system must be able to measure infinitesimal changes in the relative velocity of the two satellites, using a laser light source, which. oscillates at frequency stability better than 10(-13) in the square root of the Allan variance. The constraints placed upon the system will ultimately require that the interferometer's light-source be small, lightweight, extremely efficient, durable, and possess high frequency-stability. Present-day technology of a laser diode possesses all of these characteristics, except the last and most critical one; frequency stability. So, our ongoing efforts are all focused on the search for a method of stabilizing the oscillation frequency of the satellite-to-satellite laser-diode light source. We used a Rubidium absorption line as a frequency reference of the frequency stabilization system and the "double optical feedback" method to narrow the laser diode's oscillation linewidth, in order to improve its frequency stability. We have measured the frequency, to determine its degree of stability, by comparing the "femtosecond optical comb generator"- and laser diode-frequencies.

    DOI: 10.1117/12.576544

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  • New frequency stabilization method of a semiconductor laser using the Faraday effect of the Rb absorption line 査読

    S Ito, T Nimonji, A Sawamura, T Sato, M Ohkawa, T Maruyama

    OPTICAL DEVICES FOR FIBER COMMUNICATION IV4989   78 - 87   2003年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:SPIE-INT SOC OPTICAL ENGINEERING  

    We normally apply a precise amount of electrical. feedback into the laser injection current, to stabilize the oscillation frequency of a semiconductor laser. This feedback method usually needs a small direct modulation to the laser injection current, to obtain an error signal. This broadens the oscillation width of the laser diode, but certain applications, such as those related to coherent optical communications, benefit from, and in fact require narrower oscillation linewidth. We obtain the error signal, and stabilize the laser oscillation frequency in narrower oscillation linewidth, using the Faraday effect of the Rb absorption line. Our next task involves frequency-stabilization, which we accomplish, using a large frequency discrimination gain (G(d)). By incorporating our "PEAK" circuit, which utilizes the envelope detection method to determine the switching points between two different absorption signals corresponding to the different magnetic fields and different polarization conditions, we increases the G(d) in our stabilization system.

    DOI: 10.1117/12.474809

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  • Sensitivity dependence with respect to diaphragm dimensions in a glass-based integrated optic pressure sensor 査読

    Y Iwase, Y Okamoto, M Ohkawa, S Sekine, T Sato

    INTEGRATED OPTICS: DEVICES, MATERIALS, AND TECHNOLOGIES VII4987   256 - 263   2003年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:SPIE-INT SOC OPTICAL ENGINEERING  

    In this paper, the relationship between sensitivity and diaphragm dimensions in a glass-based integrated optic pressure sensor is described. The sensor has a rectangular diaphragm as a pressure-sensitive structure and a straight sensing waveguide across the diaphragm. The sensor operation is based on the phenomenon that a phase difference between two orthogonal guided modes is induced by the elasto-optic effect in the presence of applied pressure. The sensitivity of the sensor is theoretically known to be dependent on the thickness and side length of the diaphragm. Such dependencies are worth investigating to obtain helpful design rules for miniaturization of the sensor, but have not been examined experimentally in detail. In this study, to examine the relationship between sensitivity and thickness, two sensors were fabricated with 10 mm x 10 mm x 0.3 mm (sensor #1) and 10 mm x 10 mm x 0.22 mm (sensor #2) diaphragms.. The sensitivity of sensor #2 was larger than that of sensor #1 by a factor of 1.72, which closely agreed with the theoretical factor of 1.86. Moreover, to determine the relationship between sensitivity and side length, two more sensors, besides sensor #2, with 7mm-square (sensor #3) and 14mm-square (sensor #4) diaphragms, were fabricated with a diaphragm thickness of 0.22 mm. The measured sensitivities agreed approximately with the theoretical ones although there was a slight difference in sensor #4.

    DOI: 10.1117/12.474348

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  • Scale-reduction rule for diaphragm dimensions to miniaturize a silicon-based integrated optic pressure sensor without reducing sensitivity 査読

    A Yamada, T Tokita, M Ohkawa, S Sekine, T Sato

    INTEGRATED OPTICS: DEVICES, MATERIALS, AND TECHNOLOGIES VII4987   248 - 255   2003年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:SPIE-INT SOC OPTICAL ENGINEERING  

    In this paper, an original scale-reduction rule without sensitivity loss in integrated optic pressure sensors based on the elasto-optic effect is described. The sensor has a rectangular diaphragm as a pressure-sensitive mechanical structure and a sensing waveguide on the diaphragm. In this type of sensor, sensitivity is theoretically known to be strongly dependent on the dimensions of the diaphragm. According to the theoretical results, the sensitivity can be kept constant even if the diaphragm dimensions are reduced as long as both the side length ratio and the characteristic length remain constant. Here, the characteristic length is introduced as the cube of the shorter side length of the diaphragm divided by the square of the thickness. Such a scale-reduction rule would be very significant in the miniaturizing of a sensor without reducing sensitivity, but it has not been experimentally confirmed. In this study, the scale-reduction rule was experimentally examined using three fabricated sensors, which had the same side length ratio. and the same characteristic length. The exact dimensions of the sensors were 2.0 mm X 10 mm X 35 mum, 2.5 mm X 12.5 mm X 49 mum and 3.0 mm X 15 mm X 64 mum. The measured sensitivities of the three sensors were quite similar to each other as theoretically predicted.

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  • Silicon-based integrated optic sensor using intermodal interference between fundamental TM-like and TE-like modes 査読

    Masashi Ohkawa, Seishi Sekine, Takashi Sato

    Recent Research Developments in Electronics and Communications Part-I1   137 - 148   2002年12月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

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  • Sensitivity dependence with respect to diaphragm thickness in integrated optic pressure sensor 査読

    Yumi Okamoto, Masahiro Nanasawa, Masashi Ohkawa, Seishi Sekine, Takashi Sato

    Proceedings of APLS 2002   482 - 485   2002年10月

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  • Relationship between sensitivity and waveguide position on the diaphragm in integrated optic pressure sensors based on the elasto-optic effect 査読

    Masashi Ohkawa, Kazuhiko Hasebe, Seishi Sekine, Takashi Sato

    Applied Optics41 ( 24 ) 5016 - 5021   2002年8月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    The sensitivities of integrated optic pressure sensors with diaphragms theoretically are known to be strongly dependent on the position of the sensing waveguide on the diaphragm. According to the theoretical results, the diaphragm edge is the best position for the waveguide of a sensor based on the elasto-optic effect. The relationship between sensitivity and the waveguide position, however, has not been investigated experimentally, although it is important in the designing of such a sensor and in determining the misalignment tolerance of the sensing waveguide. In this study, this relationship in a glass-based integrated optic sensor by use of an intermodal interference was examined experimentally. © 2002 Optical Society of America.

    DOI: 10.1364/AO.41.005016

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  • Silicon-based integrated optic pressure sensor using intermodal interference between TM-like and TE-like modes 査読

    M Ohkawa, Y Shirai, T Goto, S Sekine, T Sato

    FIBER AND INTEGRATED OPTICS21 ( 2 ) 105 - 113   2002年

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:TAYLOR & FRANCIS INC  

    In this paper, a silicon-based integrated optic pressure sensor using an intermodal interference between the fundamental TM-like and TE-like modes is described. The sensor consists of a micromachined rectangular diaphragm and a straight polystyrene optical waveguide passing over the diaphragm. Its sensitivity is theoretically known to be strongly dependent on the position of the waveguide over the diaphragm. To experimentally investigate such dependence, we fabricated a sensor with a 1.2 mm x 10 mm x 20 mum diaphragm, over which waveguides were placed at 50 mum intervals. The measured phase sensitivity was 98 mrad/kPa for the waveguide nearest to the diaphragm edge. The measurement was also carried out for the other waveguides. As theoretically expected, the largest sensitivity was obtained for the waveguide nearest to the edge.

    DOI: 10.1080/014680302317244807

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  • Frequency stabilization of a semiconductor laser using the Faraday effect of the Rb absorption line - Magnatic modulation strength and stability - 査読

    T. Saga, T. Nimonji, S. Ito, T. Sato, M. Ohkawa, T. Maruyama, M. Shimba

    6th Symposium on Frequency Standards & Metrology   629 - 631   2001年6月

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    記述言語:英語   掲載種別:研究論文(その他学術会議資料等)  

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  • Increase of the inner second harmonic light of 1.5mm semiconductor lasers - Effect of two optical feedback loops - 査読

    M. Sakai, T. Ichiba, T. Seki, Y. Ohsawa, T. Sato, M. Ohkawa, T. Maruyama, M. Shimba

    6th Symposium on Frequency Standards & Metrology   635 - 637   2001年6月

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  • Frequency stabilization of a semiconductor laser using both etalon and atomic spectra as frequency refrences 査読

    T. Aiba, Y. Ohsawa, T. Sasaki, T. Sato, M. Ohkawa, T. Maruyama, M. Shimba

    6th Symposium on Frequency Standards & Metrology   632 - 634   2001年6月

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    記述言語:英語   掲載種別:研究論文(その他学術会議資料等)  

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  • Silicon-based integrated optical pressure sensor using intermodal interference between TM-like and TE-like modes 査読

    Y Shirai, T Goto, M Ohkawa, S Sekine, T Sato

    INTEGRATED OPTICS DEVICES V4277   411 - 418   2001年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:SPIE-INT SOC OPTICAL ENGINEERING  

    A silicon-based integrated optical pressure sensor using an intermodal interference between the fundamental TM-like and TE-like modes is described. The sensor consists of a micromachined rectangular diaphragm and a straight polystyrene optical waveguide passing across the diaphragm, The use of the intermodal interference has the potential advantage of shortening the sensor length since it needs neither a Y-branch nor a 3-dB coupler. In the presence of the pressure difference on the diaphragm, the phase difference is yielded between the two guided modes by an anisotropic index change induced by the elasto-optic effect. The phase difference is finally transformed into a change in light intensity by an analyzing polarizer. We fabricated a sensor with a 1.2 mm X 10 mm x 20 mum diaphragm over which the waveguides were formed at 50 mum intervals. In the experiment, a linearly-polarized He-Ne laser beam at 633 nm was coupled to the two guided modes at equal intensity. The output intensity through a polarizer was sinusoidally changed at a period of 64 kPa, corresponding to a phase sensitivity of 98 mrad/kPa, for the waveguide nearest to the diaphragm edge. The measurement was carried out for other waveguide positions. The largest sensitivity was obtained for the waveguide nearest to the diaphragm edge as theoretically expected.

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  • An experimental investigation of sensitivity dependence with respect to waveguide position on a micromachined diaphragm in a silicon-based integrated optic pressure sensor 査読

    T Goto, A Yamada, M Ohkawa, S Sekine, T Sato

    ELECTRONICS AND STRUCTURES FOR MEMS II4591   337 - 344   2001年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:SPIE-INT SOC OPTICAL ENGINEERING  

    We have been developing a silicon-based integrated optic pressure sensor using an intermodal interference between the fundamental TM-like and TE-like modes. The sensor has a micromachined diaphragm with a sensing waveguide as a pressure-sensitive structure. The sensor is theoretically known to have a strong dependence of sensitivity on the sensing waveguide on the diaphragm. According to the theoretical prediction for the sensor based on the elasto-optic effect, the waveguide should be placed along the diaphragm edge to maximize sensitivity. To date, such dependence has not been experimentally examined in detail. In this study, two sensors with 20 or more waveguides placed at 0.1 mm intervals on the diaphragm were fabricated to determine the relationship between sensitivity and waveguide position. The diaphragm dimensions were (1) 2.0 mm x 10 mm x 35 mum and (2) 3.0 mm x 15 mm x 64 mum. The ratio between width and length of each diaphragm was 1:5. The maximum sensitivity of 100 mrad/kPa was obtained for the waveguide nearest to the diaphragm edge with a wavelength of 633 nm. In addition, the measured sensitivities were very similar for the corresponding waveguide positions in the two sensors since a scaling factor, which is defined as the cube of the either side length divided by the square of the thickness, was set as a constant.

    DOI: 10.1117/12.449164

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  • Relationship between sensitivity and waveguide position on diaphragm for silicon-based integrated optic pressure sensor 査読

    A Yamada, Y Shirai, T Goto, M Ohkawa, S Sekine, T Sato

    CLEO(R)/PACIFIC RIM 2001, VOL I, TECHNICAL DIGEST   420 - 421   2001年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:IEEE  

    We have experimentally investigated how sensitivity is dependent on the position of a waveguide passing over a diaphragm in a silicon-based integrated optic pressure sensor based on the elasto-optic effect.

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  • Integrated optic pressure sensor using intermodal interference between two mutual orthogonal guided-modes 査読

    M Ohkawa, K Hasebe, C Nishiwaki, S Sekine, T Sato

    OPTICAL REVIEW7 ( 2 ) 144 - 148   2000年3月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:OPTICAL SOC JAPAN  

    we theoretically and experimentally investigated fundamental characteristics of an integrated optic pressure sensor using intermodal interference between the lowest-order TM-like and TE-like modes. The sensor consists of a rectangular diaphragm and a straight single-mode waveguide along an edge of the diaphragm. Its operation is based on a difference of phase retardations produced in the two guided modes through the photoelastic effect. The sensor was fabricated by bonding two glass substrates together: a Coming 0211 glass 300 mu m thick to form a waveguide and a thick substrate with a 10 mm x 10 mm square hole to define the diaphragm. The fabricated sensor was successfully tested using a He-Ne laser at 633 nm. The halfwave pressure was measured to be 77 kPa which is almost double the theoretical estimate.

    DOI: 10.1007/s10043-000-0144-4

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  • Glass-based integrated optic pressure sensors with a Mach-Zehnder interferometer and with an intermodal interferometer 査読

    M Ohkawa, C Nishiwaki, K Hasebe, S Sekine, T Sato

    INTEGRATED OPTICS DEVICES IV3936   309 - 318   2000年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:SPIE-INT SOC OPTICAL ENGINEERING  

    We have theoretically and experimentally investigated the fundamental characteristics of glass-based integrated optic pressure sensors with a conventional Mach-Zehnder (MZ) interferometer and with an intermodal (IM) interferometer consisting of a straight waveguide. Each sensor has a rectangular diaphragm as a pressure-sensitive mechanical structure. The sensing path of the MZ interferometer and the waveguide of the IM interferometer should be placed along the diaphragm edge to maximize the sensitivity of the sensors based on the elasto-optic effect, if the deflection of the diaphragm is small, the phase difference either between the sensing and reference waves for the MZ interferometer or between the fundamental TM-like and TE-like modes for the IM interferometer is proportional to the applied pressure. The sensors were fabricated using two glass substrates: a 0.3mm-thick Coming 0211 glass and a thick soda-lime glass with a 10mm X 10mm hole. After forming the waveguide on the 0211 glass, both substrates were bonded together with optical cement. For each sensor, the dimensions of the diaphragm were 10mm X 10mm X 0.3mm and the interaction length was 10mm. The sensitivities measured at 633mm in wavelength were 0.053rad/kPa for the MZ interferometer using the TM-like mode and 0.041rad/kPa for the IM interferometer. Each result was, however, half its theoretical estimate.

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  • Faraday effect-based semiconductor laser-frequency stabilization at the Rb absorption line. 査読

    T Kato, T Nimonji, T Sato, M Ohkawa, T Maruyama, M Shimba

    LEOS 2000 - IEEE ANNUAL MEETING CONFERENCE PROCEEDINGS, VOLS. 1 & 2   826 - 827   2000年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:IEEE  

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  • Oscillation wavelength shifts of laser diodes with or without a package in a Magnetic Field 査読

    T Sato, T Nakagawa, A Nishiie, Y Ohsawa, M Ohkawa, T Maruyama, M Shimba

    LASER DIODES AND LEDS IN INDUSTRIAL, MEASUREMENT, IMAGING, AND SENSORS APPLICATIONS II; TESTING, PACKAGING AND RELIABILITY OF SEMICONDUCTOR LASERS V3945   231 - 238   2000年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:SPIE-INT SOC OPTICAL ENGINEERING  

    We have measured the oscillation characteristic shifts of laser diodes originated from a magnetic field. We observed wavelength shifts toward the longer wavelength side, i.e., a red shift, by using the beat note between test and reference lasers at room temperature in more than five different laser types, whereas the experiments in early 60's showed a blue shift at extremely low temperature and in a very strong magnetic field. We also observed output power shifts toward the lower power side. Both characteristic shifts showed the same tendencies at increased temperature. So, we considered the magnetic field increases the temperature of the laser diodes and then two characteristics will change. Our experiment, however, showed that the amounts of changes in temperature, estimated from each characteristic shift, do not coincide with each other. At the first stage of our experiment, we removed the packaging parts of laser diodes because they are made of ferromagnetic materials. However, we recently observed the wavelength shifts using the laser diodes with the packaging parts. We are now expecting the changes of the current flow around the active region in the magnetic field can explain this discrepancy by using the correlation analysis between these two shifts.

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  • 情報検索ホログラムメモリーのレンズ系設計と情報量限界 査読

    土田 恵一, 関根征士, 大河正志, 三田元仁

    光学28 ( 3 ) 149 - 154   1999年3月

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)  

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  • Integrated optic pressure sensor using intermodal interference between TM-like and TE-like modes 査読

    K Hasebe, M Ohkawa, C Nishiwaki, S Sekine, T Sato

    OPTICAL ENGINEERING FOR SENSING AND NANOTECHNOLOGY (ICOSN'99)3740   517 - 520   1999年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:SPIE-INT SOC OPTICAL ENGINEERING  

    An integrated optic pressure sensor based on intermodal interferometry is described. The sensor consists of a straight waveguide supporting the lowest-order TM-like and TE-like modes and a rectangular diaphragm as a pressure sensitive region. The waveguide is placed along an edge of the diaphragm to maximize the sensitivity of the sensor. The output intensity of the sensor system is dependent on a difference of phase retardations induced in the two guided modes by the applied pressure via the photoelastic effect. The sensor was fabricated using two glass substrates: a Coming 0211 glass with a thickness of 300 mu m and a thick substrate with a 10mm x 10mm square hole to define the diaphragm. The two substrates were finally bonded together by UV curing adhesion after the waveguide was formed on the thin substrate. The fabricated sensor was tested using a He-Ne laser at 633nm. We successfully obtained the sinusoidal change of the output power versus the applied pressure. The halfwave pressure was evaluated to be about 80kPa experimentally.

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  • Theoretical analysis of spectral power distributions from microcavity radiators 査読

    S. Sekine, T. Kashiwagi, M. Ohkawa

    Proceedings of the 8th International Symposium on the Science & Technology of Light Sources   182 - 183   1998年12月

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    記述言語:英語   掲載種別:研究論文(その他学術会議資料等)  

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  • Bandwidth enhancement of second-harmonic generation with quadratic spatial-soliton generation versus conventional methods 査読

    M Ohkawa, RA Fuerst, GI Stegeman

    JOURNAL OF THE OPTICAL SOCIETY OF AMERICA B-OPTICAL PHYSICS15 ( 11 ) 2769 - 2772   1998年11月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:OPTICAL SOC AMER  

    A detailed numerical comparison of the bandwidth-efficiency trade-off for second-harmonic generation (SHG) achieved by the formation of two-dimensional quadratic spatial solitons versus the more conventional method of gentle focusing in the middle of a nonlinear crystal is presented. Numerical simulations for type II SHG in potassium titanyl phosphate with constant wave-vector mismatch show that the 3-dB drop-off in SHG conversion efficiency can be many multiples of pi in detuning from the phase-match condition over a large range of walk-off angles and focal positions. (C) 1998 Optical Society of America [S0740-3224(98)01911-0].

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  • Frequency stabilization of a semiconductor laser under direct FSK modulation: The modulation method and evaluation of stability 査読

    H Watanabe, H Azuma, H Nakano, T Sato, M Ohkawa, T Maruyama, M Shimba

    ELECTRICAL ENGINEERING IN JAPAN125 ( 2 ) 44 - 51   1998年11月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:SCRIPTA TECHNICA-JOHN WILEY & SONS  

    The frequency stability of a semiconductor laser deteriorated under direct frequency shift keying (FSK) when stabilization depended entirely upon an external frequency reference. Therefore, the PEAK method was devised for the purpose of improving frequency stability.
    This method requires two distinct frequency components and, therefore, will not work effectively in a communications system that produces a succession of identical frequencies, as does the FSK method on occasion. This paper, then, explains the results of our comparative analysis of the two modulation methods.
    The evaluation of frequency stability requires us to use a beat note between two stabilized laser beams, referred to here, as "signal" and "reference" lasers. The reference laser is stabilized by a method that takes advantage of the magneto-optical effect. This laser restrains the tendency of the beat note frequency to broaden in other stabilization methods, and even makes it possible to predetermine the beat frequency to be employed. The improvement in frequency stability obtained is about one order of magnitude. (C) 1998 Scripta Technica.

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  • Oscillation wavelength shift characters of a semiconductor laser in a magnetic field: Observation by using a beat note 査読

    S Matsuda, K Shibata, H Nakano, T Sato, M Ohkawa, T Maruyama, M Shimba

    ELECTRICAL ENGINEERING IN JAPAN122 ( 3 ) 46 - 54   1998年2月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:SCRIPTA TECHNICA-JOHN WILEY & SONS  

    In papers published previously, we discussed the oscillation wavelength shift of a semiconductor laser in a magnetic field at room temperature. Observations were carried out by means of a monochromator that was able to measure the oscillation wavelength shift in a steady state only and that was subject to a certain degree of measurement error. In this work, we used the beat note between two semiconductor lasers as a means of observing the wavelength shift. This method reduces the overall measurement error to about one tenth that obtained when using the monochromator-and enables us to observe the time dependence of the wavelength shift, after establishing a magnetic field. The observed wavelength shift was delayed in comparison with the square of the magnetic flux density, which is proportional to the wavelength shift in a steady state. The delay was about 0.07 s, which is much longer than we actually expected, when changing the temperature in an active layer. (C) 1998 Scripta Technica.

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  • Oscillation frequency stabilization of a semiconductor laser under direct FSK by using the PEAK method 査読

    H Nakamura, K Tamura, K Hosoya, H Nakano, T Sato, M Ohkawa, T Maruyama, M Shimba

    LASER DIODES AND APPLICATIONS III3415   182 - 191   1998年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:SPIE-INT SOC OPTICAL ENGINEERING  

    The oscillation frequency of a semiconductor laser must be stabilized in coherent optical communications systems that use such devices, because the frequency fluctuates according to variations in either temperature or injection current. Therefore, we set about the task of stabilizing it, using the Rb-D-2 absorption line as an external frequency reference and negative feedback control. This method of stabilization requires the application of small sine wave modulation to obtain error signal by synchronous detection method While the highly sensitive control ensures improved signal stability, frequency stability is deteriorated under direct FSK (Frequency Shift Keying), because the oscillation spectrum of a semiconductor laser is broadened. We, therefore, devised the. "PEAK method", which improves frequency stability under direct FSK. The accurate measurement of frequency stability requires that the beat note between two stabilized laser frequencies, the signal and reference lasers, be measured. But beat note was sometimes outside the limits of our measuring equipment The reference laser frequency was therefore adjusted by using the magneto-optical effect to control the beat note frequency within measurable limits of this work. We calculated the square root of the Allan variance to estimate the frequency stability, thereby confirming the effectiveness of PEAK method.

    DOI: 10.1117/12.326633

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  • Oscillation frequency stabilization of a semiconductor laser using the magneto-optical effects of Rb-D-2 absorption line 査読

    T Nimonji, K Ishikawa, H Nakano, H Nakamura, T Sato, M Ohkawa, T Maruyama, M Shimba

    LASER DIODES AND APPLICATIONS III3415   17 - 28   1998年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:SPIE-INT SOC OPTICAL ENGINEERING  

    The oscillation frequency of semiconductor lasers fluctuates by a temperature or an injection current change. Semiconductor lasers are now used in many application fields such as optical fiber communications systems, compact disk and laser disk systems, and others, because these application fields don't need the high frequency stability in their light source. Therefore, we must stabilize the oscillation frequency of semiconductor lasers if we use them in a coherent optical communications or other coherent systems.
    Some frequency stabilization experiments of semiconductor lasers using external frequency references have been reported in recent years. We have also stabilized them using the Rb-D-2 absorption line as an external frequency reference. Applying a small modulation directly to the injection current usually performs these stabilization methods. But the oscillation spectrum of the semiconductor laser is broadened by the modulation in this method.
    So we devised two stabilization methods without any direct modulation, which use the magneto-optical effects called the Zeeman and the Faraday effects, and stabilized the oscillation frequency of the semiconductor laser. As a result, we got high frequency stability without any spectrum broadening caused by the modulation. The stabilized frequency was tuned in a wide range at almost the same stability condition.
    Moreover, we devised an optical setup, which produces a high sensitive error signal between the reference frequency and the laser oscillation frequency. This method, which we named "PEAK method", is also combined with the Zeeman effect to improve the frequency controllability.

    DOI: 10.1117/12.326635

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  • Theoretical Evaluation of Spectral Power Distributions of Radiant Energy from Microcavities 査読

    Seishi Sekine, Masatoshi Ueno, Hiroaki Suzuki, Masashi Ohkawa

    Journal of Light and Visual Environment22 ( 1 ) 12 - 16   1998年

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    Characteristics of radiation from microcavities are investigated to verify the luminous efficacy of microcavity radiator that was estimated by John F. Waymouth in 1989. Electromagnetic waves in a rectangular microcavity and a cylindrical microcavity were analyzed based on the waveguide theory. The modes of electromagnetic waves in the microcavities are analyzed using a normalized eigenfunction. The conductivity and permittivity of metals are obtained by analyzing the motion equation of the free electron in the metals. The skin depth of tungsten is estimated with the emissivity of tungsten based on electromagnetic theory. Accordingly it is estimated that the luminous efficacy of radiation from the microcavity is expected to reach 118 Im/W. © 1998, The Illuminating Engineering Institute of Japan. All rights reserved.

    DOI: 10.2150/jlve.22.1_12

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  • Oscillation wavelength shifts of visible and infrared laser diodes in a magnetic field 査読

    T Sato, K Matsumoto, S Toujou, T Nakagawa, H Nakano, M Ohkawa, T Maruyama, M Shimba

    LASER DIODES AND APPLICATIONS III3415   173 - 181   1998年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:SPIE-INT SOC OPTICAL ENGINEERING  

    The shift, which occurs in the oscillation wavelength of a semiconductor laser in a magnetic field, has been the subject of great interest, since the early 60's. During the course of the investigation, the observed shift was toward the short wavelength side, i.e., a blue shift, which was well accounted for, in terms of the Landau level. At present, we are studying how wavelength shift is affected, by applying, at room temperature, a relatively weak magnetic field, using recently developed visible and infrared diode lasers. By doing so, we have observed a red shift and a decrease in laser output-power, under a certain magnetic field conditions in its strength and direction. Since these two changes in wavelength and output power correspond to those observed at higher temperatures, we assumed that the orientation of the magnetic field affects current density in laser diodes. And then it alters temperatures around the active layer, which in turn influence oscillation wavelength and laser output-power. Also of note, was the fact that the red shift and the decrease in laser output-power occurred simultaneously, revealing an almost linear dependency on one another. This might possibly explain the heat, which developed as the result of applying the magnetic field. However, we recently observed an instance, in which visible MQW laser diodes did not exhibit this linear dependence. Because this phenomenon cannot be traced simply to the effects of heat, we are now examining it in terms of current-density alteration.

    DOI: 10.1117/12.326632

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  • Zeeman effect-based control-signal improvement for frequency stabilization of a semiconductor laser 査読

    H Nakano, N Watanabe, T Sato, M Ohkawa, T Maruyama, M Shimba

    ELECTRONICS AND COMMUNICATIONS IN JAPAN PART II-ELECTRONICS80 ( 8 ) 20 - 29   1997年8月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:SCRIPTA TECHNICA-JOHN WILEY & SONS  

    We have stabilized the oscillation frequency of a 780-nm-band semiconductor laser using the D-2 absorption line of Rb atoms. The absorption line has a spectral width due to the natural width and Doppler width, which limits the stability of laser performance. In order to minimize the spectral spread of the absorption line, a Doppler effect-free absorption line whose spectral spread is close to the natural width was obtained by saturated absorption spectroscopy and was used for stabilization of the laser oscillation frequency However, the spectral width of the absorption line could not be further narrowed by optical means alone. In this study, the spectral width of the reference signal was further narrowed using the Zeeman effect of the Rb atomic absorption line and the newly developed PEAK and BOTTOM methods. Using this reference signal, the width of the frequency discrimination curve was narrowed. As a result, the laser oscillation frequency more accurately tracks the reference frequency. In addition it was confirmed that the frequency discrimination curve could be swept. (C) 1998 Scripta Technica.

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  • Integrated optic micropressure sensor using ring resonator 査読

    M Ohkawa, T Abe, S Sekine, T Sato

    ELECTRONICS AND COMMUNICATIONS IN JAPAN PART II-ELECTRONICS79 ( 4 ) 1 - 10   1996年4月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:SCRIPTA TECHNICA PUBL  

    In this paper, sensitivity improvement of integrated optic micropressure sensors is discussed. The sensor is composed of a diaphragm and a ring resonator that is a multiple interference optical circuit. A part of the waveguide of the ring resonator is on the diaphragm. When a pressure is applied to the sensor, the diaphragm is deformed and the refractive index changes slightly so that a phase shift is induced on the guided wave propagating on the diaphragm. From the change of the resonant frequency caused by this phase change, the magnitude of the applied pressure is detected. In this study, particular emphasis is on the relationship between the diaphragm dimensions and the sensor sensitivity. From the analysis of the sensor operation, it is concluded that the use of a square-shaped diaphragm with a waveguide of the ring resonator at the edge in addition to employing the TM-like mode is most suited for a highly sensitive sensor. Further, from the evaluation of the minimum detectable pressure, it is expected that an integrated optic microprocessor sensor can be realized which is sensitive to such low pressure as underwater acoustics.

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  • FREQUENCY STABILIZATION OF A SEMICONDUCTOR-LASER UNDER DIRECT FREQUENCY-SHIFT KEYING USING THE SATURATED ABSORPTION SIGNAL 査読

    T SATO, J MIZUMOTO, Y KOBAYASHI, M ISHIGURO, M OHKAWA, T MARUYAMA, M SHIMBA

    JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS SHORT NOTES & REVIEW PAPERS33 ( 3B ) 1608 - 1613   1994年3月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:JAPAN J APPLIED PHYSICS  

    The oscillating frequency of a semiconductor laser was stabilized at the Rb-D2 absorption line under direct frequency shift keying (FSK). The control system equipped with a peak-hold circuit provided the frequency stability of 10(-9) > sigma(2, tau) > 10(-12) at the averaging time 0.05 s < tau < 40 s when the Doppler-limited absorption line was used as a frequency reference. This stability was better than that obtained by the traditional control system without the peak-hold circuit under direct FSK. Using the saturated absorption signal, the frequency stability was improved more than one order of magnitude in comparison with that obtained using the Doppler-limited absorption signal.

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  • OSCILLATION WAVELENGTH SHIFTS OF DIODE-LASERS IN A MAGNETIC-FIELD 査読

    T SATO, H KAWASHIMA, T HOSHI, S YAMAMOTO, M OHKAWA, T MARUYAMA, M SHIMBA

    LASER DIODE TECHNOLOGY AND APPLICATIONS VI2148   431 - 439   1994年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:SPIE - INT SOC OPTICAL ENGINEERING  

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  • Oscillation wavelength shift of GaAlAs laser diodes in a magnetic field 査読

    Takashi Sato, Hidetoshi Kawashima, Toshio Nakamura, Masashi Ohkawa, Takeo Maruyama, Minoru Shimba

    Electronics and Communications in Japan (Part II: Electronics)76 ( 4 ) 13 - 21   1993年

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    The wavelength shift of laser diodes in a magnetic field has been known for a long time. However, most of the studies have been performed at very low temperatures in a strong magnetic field. An experiment is carried out using laser diodes which oscillate at room temperature and found that the wavelength shift changed significantly, being sensitive to an inner structure. Further, the wavelength shift occurred depending on a magnetic field direction. Previously, the wavelength shift was explained on the basis of the Landau level at very low temperatures in a strong magnetic field. However, such Landau levels are not formed in a relatively weak magnetic field at room temperature
    and, thus, the present result cannot be accounted for by the existing theories. This paper describes the experimental results of various types of GaAlAs laser diodes and discusses the mechanism of the wavelength shift and the wavelength control. Copyright © 1993 Wiley Periodicals, Inc., A Wiley Company

    DOI: 10.1002/ecjb.4420760402

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▶ 全件表示

書籍等出版物

  • マイクロオプトメカトロニクスハンドブック

    大河正志, 井筒雅之, 五十嵐伊勢美, 江刺正喜, 藤田博之編( 担当: 共著 ,  範囲: 3.3節 光集積回路センサ)

    朝倉書店  1997年12月 

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    記述言語:日本語

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MISC

  • Optical range finder using semiconductor laser frequency noise

    T. Saito, K. Kondo, Y. Tokutake, S. Maehara, K. Doi, H. Arai, T. Sato, M. Ohkawa, Y. Ohdaira, S. Sakamoto

    Proceedings of SPIE - The International Society for Optical Engineering9576   2015年1月

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    © COPYRIGHT SPIE. Downloading of the abstract is permitted for personal use only. Semiconductor laser range-finder systems use so-called time-of-flight methods that require us to modulate semiconductor lasers intensity and frequency, and detect those of reflected lights, in order to compare optical paths to the reference and the target. But, accurate measurement requires both high-speed modulation and detection systems. By taking advantage of semiconductor lasers broad-spectrum frequency noise, which has a range of up to a few GHz, and converting it to intensity noise, we were able to generate a set of high-speed physical random numbers that we used to precisely measure the distance. We tuned the semiconductor lasers oscillation frequencies loosely to the Rb absorption line and converted their frequency noise to intensity noise, in the light transmitted. Observed through a frequency discriminator, beams traveling along two different paths will always share intensity noise patterns, but there is a time lag. We calculate the cross-correlation of the two signals by sweeping their time lags. The one with the highest degree of correlation was that corresponding to the difference in the length of the two optical paths. Through our experiments, we confirmed that the system was accurate up to a distance of 50 m, at a resolution of 0.03 m, when the sampling rate was adjusted to 0.2 ns.

    DOI: 10.1117/12.2187963

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  • 半導体レーザの周波数雑音を用いた物理乱数の生成 : 光源の特性による影響 (光エレクトロニクス)

    水谷 直博, 長谷川 真俊, 新井 秀明, 前原 進也, 土井 康平, 佐藤 孝, 大平 泰生, 大河 正志, 坂本 秀一

    電子情報通信学会技術研究報告 = IEICE technical report : 信学技報114 ( 186 ) 59 - 62   2014年8月

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    記述言語:日本語   出版者・発行元:一般社団法人電子情報通信学会  

    インターネット社会において、暗号技術は必要不可欠なものとなっている。現在多く使われている疑似乱数を用いた暗号は、解読に膨大な時間がかかることを担保に安全性を保っている。しかし、高速処理可能なコンピュータの登場により、解読される危険性がでてきた。一方で、理論上解読不可能な量子暗号通信の研究が進んでおり、物理乱数が大量に必要とされている。本研究では、半導体レーザの周波数雑音を用いて物理乱数の生成を行った。今回は、面発光型レーザ(VCSEL)とファブリ・ペロー型レーザ(FPLD)を用いて乱数生成を行い、VCSELでは120Gb/s、ではFPLDでは40Gb/sで乱数生成できた。

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  • 半導体レーザの周波数雑音を利用した光距離計測の検討 (光エレクトロニクス)

    近藤 勝軌, 齊藤 高大, 徳嵩 裕也, 新井 秀明, 前原 進也, 土井 康平, 佐藤 孝, 大平 泰生, 大河 正志, 坂本 秀一

    電子情報通信学会技術研究報告 = IEICE technical report : 信学技報114 ( 186 ) 63 - 66   2014年8月

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    記述言語:日本語   出版者・発行元:一般社団法人電子情報通信学会  

    半導体レーザは,低コスト,軽量,低電力,長寿命などの利点から,光距離計測の光源として用いられている.また,半導体レーザは,その発振周波数が変動する周波数雑音を持っており,私たちはそれを用いて物理乱数生成を行ってきた.本研究では,この生成された物理乱数を用いた新しい光距離計測法を考案し計測を行ったので報告する.通常の光距離計測は,パルスなどの変調信号を用いているが,本方式では変調信号の代わりに周波数雑音を用いた.周波数変動は,Rb-D_2吸収線を用いて透過光強度に変換し,距離測定を行った.これにより変調を加えず,0.06mの分解能で,50mまでの距離計測を行うことができた.また,サンプリングレートを変えずに分解能の向上を図る検討を行ったためここに報告する.

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  • C-4-14 半導体レーザの周波数雑音特性を用いた物理乱数生成 : 発振幅狭窄化が物理乱数生成への影響に関する考察(C-4.レーザ・量子エレクトロニクス,一般セッション)

    酒井 翔太, 新井 秀明, 齋藤 高大, 大河 正志, 大平 泰生, 坂本 秀一, 佐藤 孝

    電子情報通信学会総合大会講演論文集2014 ( 1 )   2014年3月

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    記述言語:日本語   出版者・発行元:一般社団法人電子情報通信学会  

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  • 21aSB-4 スペース重力波アンテナDECIGO計画(55) : DECIGO/DPFの概要(21aSB 重力波(KAGRA,DECIGO,TOBA,検出器),宇宙線・宇宙物理領域)

    安東 正樹, 川村 静児, 瀬戸 直樹, 中村 卓史, 坪野 公夫, 佐藤 修一, 田中 貴浩, 船木 一幸, 沼田 健司, 神田 展行, 井岡 邦仁, 高島 健, 横山 順一, 阿久津 智忠, 武者 満, 上田 暁俊, 麻生 洋一, 新谷 昌人, 坂井 真一郎, 青柳 巧介, 我妻 一博, 浅田 秀樹, 新井 宏二, 池上 健, 石川 毅彦, 石崎 秀晴, 石原 秀樹, 和泉 究, 市來 淨與, 伊東 宏之, 伊藤 洋介, 井上 開輝, 植田 憲一, 牛場 崇文, 歌島 昌由, 江口 智士, 江尻 悠美子, 榎 基宏, 戎崎 俊一, 江里口 良治, 大石 奈緒子, 大河 正志, 大橋 正健, 大原 謙一, 大渕 喜之, 岡田 健志, 岡田 則夫, 奥富 弘基, 河島 信樹, 川添 史子, 河野 功, 木内 建太, 岸本 直子, 國中 均, 國森 裕生, 黒田 和明, 黒柳 幸子, 小泉 宏之, 洪 鋒雷, 郡 和範, 穀山 渉, 苔山 圭以子, 古在 由秀, 小嶌 康史, 固武 慶, 小林 史歩, 権藤 里奈, 西條 統之, 齊藤 遼, 阪上 雅昭, 阪田 紫帆里, 佐合 紀親, 佐々木 節, 佐藤 孝, 柴田 大, 柴田 和憲, 正田 亜八香, 真貝 寿明, 末正 有, 杉山 直, 鈴木 理恵子, 諏訪 雄大, 宗宮 健太郎, 祖谷 元, 高野 忠, 高橋 走, 高橋 慶太郎, 高橋 弘毅, 高橋 史宜, 高橋 龍一, 高橋 竜太郎, 高森 昭光, 田越 秀行, 田代 寛之, 田中 伸幸, 谷口 敬介, 樽家 篤史, 千葉 剛, 陳 たん, 辻川 信二, 常定 芳基, 豊嶋 守生, 鳥居 泰男, 中尾 憲一, 中澤 知洋, 中須賀 真一, 中野 寛之, 長野 重夫, 中村 康二, 中山 宜典, 西澤 篤志, 西田 恵里奈, 西山 和孝, 丹羽 佳人, 能見 大河, 橋本 樹明, 端山 和大, 原田 知広, 疋田 渉, 姫本 宣朗, 平林 久, 平松 尚志, 福嶋 美津広, 藤田 龍一, 藤本 眞克, 二間瀬 敏史, 細川 瑞彦, 堀澤 秀之, 前田 恵一, 松原 英雄, 松本 伸之, 道村 唯太, 宮川 治, 宮本 雲平, 三代木 伸二, 向山 信治, 森澤 理之, 森本 睦子, 森脇 成典, 八木 絢外, 山川 宏, 山崎 利孝, 山元 一広, 吉田 至順, 吉野 泰造, 柳 哲文, 若林 野花

    日本物理学会講演概要集69 ( 0 )   2014年

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    記述言語:日本語   出版者・発行元:一般社団法人日本物理学会  

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  • 周波数安定化半導体レーザーによる物理乱数生成システムの構築

    新井秀明, 前原進也, 土井康平, 佐藤孝, 大平泰生, 坂本秀一, 大河正志

    応用物理学会秋季学術講演会講演予稿集(CD-ROM)74th   ROMBUNNO.16P-P2-3   2013年8月

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  • 半導体レーザの周波数雑音特性を用いた物理乱数生成の検討 : 発振周波数狭窄化が物理乱数に及ぼす影響に関する研究 (レーザ・量子エレクトロニクス)

    古川 元一, 斎藤 高大, 酒井 翔太, 新井 秀明, 前原 進也, 土井 康平, 佐藤 孝, 大河 正志, 坂本 秀一, 大平 泰生

    電子情報通信学会技術研究報告 = IEICE technical report : 信学技報113 ( 190 ) 5 - 10   2013年8月

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    記述言語:日本語   出版者・発行元:一般社団法人電子情報通信学会  

    半導体レーザから出力された光は強度及び周波数が変動する高速の雑音特性を持っている。本研究ではその周波数雑音を、周波数弁別器を利用して光強度に変換し、その信号から物理乱数の高速生成を行っている。今回の研究では半導体レーザの発振幅を外部共振器を利用して狭窄化し、そのときの物理乱数とフリーランニング時の物理乱数の比較を行った。

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  • 半導体レーザの広帯域周波数雑音を利用した物理乱数の高速生成 (レーザ・量子エレクトロニクス)

    近藤 尭信, 前原 進也, 水谷 直博, 新井 秀明, 土井 康平, 佐藤 孝, 坂本 秀一, 大平 泰生, 大河 正志, SHIMIZU Naoya

    電子情報通信学会技術研究報告 = IEICE technical report : 信学技報113 ( 190 ) 1 - 4   2013年8月

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    記述言語:日本語   出版者・発行元:一般社団法人電子情報通信学会  

    近年の高度情報化社会の発展に伴い、インターネットなどを通じ情報を交換する機会が増加し、情報の保護という観点から情報の暗号化が日々重要視されている。そこで、解読が困難である「物理乱数」が注目を集めているが、高速に生成することは困難であるとされている。本研究では、「物理乱数」を高速に生成する方法として、半導体レーザが持つ、出力光の周波数が広帯域にかつ不規則に変化する物理現象である「周波数雑音特性」を利用する。Rbの吸収線を利用しレーザ光の周波数の変化を、光強度の変化に変換することで検出し、それをデジタル数値化することで「物理乱数」を高速に生成している。

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  • 半導体レーザの周波数雑音特性を応用した光距離計測の検討 (レーザ・量子エレクトロニクス)

    清水 直弥, 前原 進也, 土井 康平, 新井 英明, 佐藤 孝, 大河 正志, 大平 泰生, 坂本 秀一

    電子情報通信学会技術研究報告 = IEICE technical report : 信学技報113 ( 190 ) 11 - 14   2013年8月

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    記述言語:日本語   出版者・発行元:一般社団法人電子情報通信学会  

    半導体レーザは,自然放出光の影響による振幅揺らぎとキャリア密度の変動から,屈折率の変動,すなわち発振周波数の変動となる周波数揺らぎを保有している.本研究では,半導体レーザの周波数雑音特性を積極的に利用した新たな応用として,光距離計測が可能か検討した.我々が提案する光距離計測では,周波数雑音の比較により、距離差を求める.それにより,光源の変調を必要とせず,遠距離でも測定精度が変わらないレーザ距離計測が可能と考えられる.ここでは,提案手法により0〜35 mの光距離計測検討を行ったので報告する.

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  • 半導体レーザの周波数雑音を用いた物理乱数の生成 : 発振幅が物理乱数に及ぼす影響に関する考察 (レーザ・量子エレクトロニクス)

    齊藤 高大, 新井 秀明, 古川 元一, 酒井 翔太, 佐藤 孝, 坂本 秀一, 大河 正志

    電子情報通信学会技術研究報告 = IEICE technical report : 信学技報113 ( 49 ) 17 - 21   2013年5月

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    記述言語:日本語   出版者・発行元:一般社団法人電子情報通信学会  

    半導体レーザは、自然放出光の影響により、活性層内のキャリア密度の変動がおき、屈折率が変化し、発振周波数が変動する周波数雑音を内在している。我々は、この非周期的で高速な周波数雑音を積極的に用い、物理乱数生成システムを構築してきた。周波数雑音による半導体レーザの発振周波数変動幅は、主に発振幅として表現される。本研究では、フリーランニング半導体レーザと線幅の細い外部共振器半導体レーザを用いて、それぞれ乱数を生成した。生成した各乱数列を暗号用乱数検定FIPS140-2に通し、評価結果を比較し、乱数を生成する半導体レーザの発振幅が乱数性に及ぼす影響を考察した。

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  • 半導体レーザーの周波数雑音を利用した物理乱数生成と距離計測

    土井康平, 前原進也, 新井秀明, 佐藤孝, 大平泰生, 坂本秀一, 大河正志

    応用物理学会学術講演会講演予稿集(CD-ROM)73rd   ROMBUNNO.12A-PA1-1   2012年8月

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  • 半導体レーザの雑音特性を用いた物理乱数の生成 : 発振周波勢安定化が物理乱数に及ぼす影響に関する考察

    齊藤 高大, 古川 元一, 新井 秀明, 佐藤 孝, 坂本 秀一, 大河 正志

    電子情報通信学会技術研究報告. LQE, レーザ・量子エレクトロニクス112 ( 184 ) 5 - 8   2012年8月

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    記述言語:日本語   出版者・発行元:一般社団法人電子情報通信学会  

    半導体レーザは、キャリア密度の変動で利得や屈折率が変動し、単一縦モード発振中でも周波数雑音が発生する。我々はこの半導体レーザの周波数雑音を、周波数弁別器を用いて光強度雑音に変換し、更にA/Dで2進数にすることで、物理乱数の生成を行ってきた。しかし、半導体レーザの発振周波数が大きく変動すると、生成される乱数の乱数性が劣化する可能性がある。そのため、安定化半導体レーザによる物理乱数の乱数検定通過率を測定した。

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  • 面発光型半導体レーザの周波数雑音を利用した物理乱数の生成に関する研究

    川上 航平, 前原 進也, 土井 康平, 新井 秀明, 近藤 尭信, 清水 直弥, 佐藤 孝, 坂本 秀一, 大平 泰生, 大河 正志

    電子情報通信学会技術研究報告. LQE, レーザ・量子エレクトロニクス112 ( 184 ) 9 - 12   2012年8月

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    記述言語:日本語   出版者・発行元:一般社団法人電子情報通信学会  

    大規模シミュレーションや通信の暗号化を行う際に現行では一般的に擬似乱数が用いられている.しかし,近年物理乱数への期待が非常に高まっており,半導体レーザカオスを利用した物理乱数の高速生成も報告されている.そこで本研究では,面発光型半導体レーザの周波数雑音を,Rb原子の吸収線を介して光強度雑音に変換し,A/Dコンバータで2進数列にすることで乱数を生成させ,より高速な物理乱数生成の可能性を検討した.

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  • 24pGJ-6 スペース重力波アンテナDECIGO計画(36) : DECIGO/DPF(24pGJ 重力波(DECIGOなど),宇宙線・宇宙物理領域)

    安東 正樹, 川村 静児, 瀬戸 直樹, 中村 卓史, 坪野 公夫, 佐藤 修一, 田中 貴浩, 船木 一幸, 沼田 健司, 神田 履行, 井岡 邦仁, 高島 健, 横山 順一, 青柳 巧介, 我妻 一博, 阿久津 智忠, 浅田 秀樹, 麻生 洋一, 新井 宏二, 新谷 昌人, 池上 健, 石川 毅彦, 石崎 秀晴, 石徹白 晃治, 石原 秀樹, 和泉 究, 市來 淨興, 伊東 宏之, 伊藤 洋介, 井上 開輝, 上田 暁俊, 植田 憲一, 歌島 昌由, 江口 智士, 江尻 悠美子, 榎基 宏, 戎崎 俊一, 江里口 良治, 大石 奈緒子, 大河 正志, 大橋 正健, 大原 〓一, 大淵 喜之, 岡田 健志, 岡田 則夫, 河島 信樹, 川添 史子, 河野 功, 木内 建太, 岸本 直子, 國中 均, 國森 裕生, 黒田 和明, 黒柳 幸子, 小泉 宏之, 洪 鋒雷, 郡 和範, 穀山 渉, 苔山 圭以子, 古在 由秀, 小嶌 康史, 固武 慶, 小林 史歩, 西條 統之, 齊藤 遼, 坂井 真一郎, 阪上 雅昭, 阪田 紫帆里, 佐合 紀親, 佐々木 節, 佐藤 孝, 柴田 大, 正田 亜八香, 真貝 寿明, 杉山 直, 鈴木 理恵子, 諏訪 雄大, 宗宮 健太郎, 祖谷 元, 高野 忠, 高橋 走, 高橋 慶太郎, 高橋 忠幸, 高橋 弘毅, 高橋 史宜, 高橋 龍一, 高橋 竜太郎, 高森 昭光, 田越 秀行, 田代 寛之, 田中 伸幸, 谷口 敬介, 樽家 篤史, 千葉 剛, 陳 たん, 辻川 信二, 常定 芳基, 豊嶋 守生, 鳥居 泰男, 中尾 憲一, 中澤 知洋, 中須賀 真一, 中野 寛之, 長野 重夫, 中村 康二, 中山 宜典, 西澤 篤志, 西田 恵里奈, 西山 和孝, 丹羽 佳人, 能見 大河, 橋本 樹明, 端山 和大, 原田 知広, 疋田 渉, 姫本 宣朗, 平林 久, 平松 尚志, 福嶋 美津広, 藤田 龍一, 藤本 眞克, 二間瀬 敏史, 細川 端彦, 堀澤 秀之, 前田 恵一, 松原 英雄, 松本 伸之, 道村 唯太, 宮川 治, 宮本 雲平, 三代木 伸二, 向山 信治, 武者 満, 森澤 理之, 森本 睦子, 森脇 成典, 八木 絢外, 山川 宏, 山崎 利孝, 山元 一広, 吉田 至順, 吉野 泰造, 柳 哲文, 若林 野花

    日本物理学会講演概要集67 ( 0 )   2012年

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    記述言語:日本語   出版者・発行元:一般社団法人日本物理学会  

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  • 半導体レーザの周波数雑音を応用した高速物理乱数生成

    土井 康平, 新井 秀明, 前原 進也, 高森 大希, 松本 良彦, 佐藤 孝, 大平 泰生, 坂本 秀一, 大河 正志

    電子情報通信学会技術研究報告. LQE, レーザ・量子エレクトロニクス111 ( 56 ) 9 - 12   2011年5月

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    記述言語:日本語   出版者・発行元:一般社団法人電子情報通信学会  

    周波数弁別器によって半導体レーザの周波数雑音は簡単に検出することができる.この周波数雑音は広帯域に分布し,高速な物理乱数生成のソースとして有用であると見込まれる.また,周波数雑音を利用した物理乱数生成器は,周波数雑音を検出するための光学系が単純なため,装置の小型化が容易という利点がある.今回,実験的に半導体レーザの周波数雑音を用いて物理乱数生成を生成し,国際標準とされるNIST SP 800-22によって評価した結果を報告する.

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  • 28aGS-1 スペース重力波アンテナDECIGO計画(30) : 設計・計画(28aGS 重力波(DECIGOなど),宇宙線・宇宙物理領域)

    川村 静児, 安東 正樹, 瀬戸 直樹, 佐藤 修一, 中村 卓史, 坪野 公夫, 船木 一幸, 横山 順一, 神田 展行, 田中 貴浩, 沼田 健司, 高島 健, 井岡 邦仁, 青柳 巧介, 我妻 一博, 阿久津 智忠, 浅田 秀樹, 麻生 洋一, 新井 宏二, 新谷 昌人, 池上 健, 石川 毅彦, 石崎 秀晴, 石徹白 晃治, 石原 秀樹, 和泉 究, 市來 浮與, 伊東 宏之, 伊藤 洋介, 井上 開輝, 上田 暁俊, 植田 憲一, 歌島 昌由, 江尻 悠美子, 榎 基宏, 戎崎 俊一, 江里口 良治, 大石 奈緒子, 大河 正志, 大橋 正健, 大原 謙一, 大渕 喜之, 岡田 健志, 岡田 則夫, 河島 信樹, 川添 史子, 河野 功, 木内 建太, 岸本 直子, 國中 均, 國森 裕生, 黒田 和明, 黒柳 幸子, 小泉 宏之, 洪 鋒雷, 郡 和範, 穀山 渉, 苔山 圭以子, 古在 由秀, 小嶌 康史, 固武 慶, 小林 史歩, 西條 統之, 齊藤 遼, 坂井 真一郎, 阪上 雅昭, 阪田 紫帆里, 佐合 紀親, 佐々木 節, 佐藤 孝, 柴田 大, 正田 亜八香, 真貝 寿明, 杉山 直, 鈴木 理恵子, 諏訪 雄大, 宗宮 健太郎, 祖谷 元, 高野 忠, 高橋 走, 高橋 慶太郎, 高橋 忠幸, 高橋 弘毅, 高橋 史宜, 高橋 龍一, 高橋 竜太郎, 高森 昭光, 田越 秀行, 田代 寛之, 田中 伸幸, 谷口 敬介, 樽家 篤史, 千葉 剛, 陳 たん, 辻川 信二, 常定 芳基, 豊嶋 守生, 鳥居 泰男, 内藤 勲夫, 中尾 憲一, 中澤 知洋, 中須賀 真一, 中野 寛之, 長野 重夫, 中村 康二, 中山 宜典, 西澤 篤志, 西田 恵里奈, 西山 和孝, 丹羽 佳人, 能見 大河, 橋本 樹明, 端山 和大, 原田 知広, 疋田 渉, 姫本 宣朗, 平林 久, 平松 尚志, 福嶋 美津広, 藤田 龍一, 藤本 眞克, 二間瀬 敏史, 細川 瑞彦, 堀澤 秀之, 前田 恵一, 松原 英雄, 松本 伸之, 道村 唯太, 宮川 治, 宮本 雲平, 三代木 伸二, 向山 信治, 武者 満, 森澤 理之, 森本 睦子, 森脇 成典, 八木 絢外, 山川 宏, 山崎 利孝, 山元 一広, 吉田 至順, 吉野 泰造, 柳 哲文, 若林 野花

    日本物理学会講演概要集66 ( 0 )   2011年

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    記述言語:日本語   出版者・発行元:一般社団法人日本物理学会  

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  • BI-1-7 レーザー干渉計型宇宙重力波アンテナ : DECIGO計画(BI-1.宇宙へ応用されるレーザ技術,ソサイエティ企画)

    武者 満, 川村 静児, 安東 正樹, 瀬戸 直樹, 佐藤 修一, 中村 卓史, 坪野 公夫, 高島 健, 船木 一幸, 沼田 健司, 神田 展行, 田中 貴浩, 井岡 邦仁, 青柳 巧介, 我妻 一博, 浅田 秀樹, 麻生 洋一, 新井 宏二, 新谷 昌人, 池上 健, 石川 毅彦, 石崎 秀晴, 石徹白 晃治, 石原 秀樹, 和泉 究, 市來 淨與, 伊東 宏之, 伊藤 洋介, 井上 開輝, 上田 暁俊, 植田 憲一, 歌島 昌由, 江尻 悠美子, 榎 基宏, 戎崎 俊一, 江里口 良治, 大石 奈緒子, 大河 正志, 大橋 正健, 大原 謙一, 大渕 喜之, 岡田 健志, 河島 信樹, 川添 史子, 河野 功, 木内 建太, 岸本 直子, 國中 均, 國森 裕生, 黒田 和明, 小泉 宏之, 洪 鋒雷, 郡 和範, 穀山 渉, 苔山 圭以子, 古在 由秀, 小嶌 康史, 固武 慶, 小林 史歩, 西條 統之, 齊藤 遼, 坂井 真一郎, 阪上 雅昭, 阪田 紫帆里, 佐合 紀親, 佐々木 節, 佐藤 孝, 柴田 大, 真貝 寿明, 杉山 直, 鈴木 理恵子, 諏訪 雄大, 宗宮 健太郎, 祖谷 元, 高野 忠, 高橋 走, 高橋 慶太郎, 高橋 忠幸, 高橋 弘毅, 高橋 史宜, 高橋 龍一, 高橋 竜太郎, 高森 昭光, 田越 秀行, 田代 寛之, 谷口 敬介, 樽家 篤史, 千葉 剛, 辻川 信二, 常定 芳基, 豊嶋 守生, 鳥居 泰男, 内藤 勲夫, 中尾 憲一, 中澤 知洋, 中須賀 真一, 中野 寛之, 長野 重夫, 中村 康二, 中村 真大, 中山 宜典, 西澤 篤志, 西田 恵里奈, 西山 和孝, 丹羽 佳人, 能見 大河, 橋本 樹明, 端山 和大, 原田 知広, 疋田 渉, 姫本 宣朗, 平林 久, 平松 尚志, 福嶋 美津広, 藤田 龍一, 藤本 眞史, 二間瀬 敏文, 細川 瑞彦, 堀澤 秀之, 前田 恵一, 松原 英雄, 蓑 泰志, 宮川 治, 宮本 雲平, 三代木 伸二, 向山 信治, 森澤 理之, 森本 睦子, 森脇 成典, 八木 絢外, 山川 宏, 山崎 利孝, 山元 一広, 柳 哲文, 横山 順一, 吉田 至順, 吉野 泰造, 若林 野花, Sun Ke-Xun, Musha Mitsuru

    電子情報通信学会総合大会講演論文集2010 ( 1 ) SS_85 - SS-86   2010年3月

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    記述言語:日本語   出版者・発行元:一般社団法人電子情報通信学会  

    本文データは学協会の許諾に基づきCiNiiから複製したものである

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  • 21aBH-1 スペース重力波アンテナDECIGO計画(24) : 設計・計画(21aBH 重力波,宇宙線・宇宙物理領域)

    川村 静児, 安東 正樹, 瀬戸 直樹, 佐藤 修一, 中村 卓史, 坪野 公夫, 高島 健, 船木 一幸, 沼田 健司, 神田 展行, 田中 貴浩, 井岡 邦仁, 青柳 巧介, 我妻 一博, 浅田 秀樹, 麻生 洋一, 新井 宏二, 新谷 昌人, 池上 健, 石川 毅彦, 石崎 秀晴, 石徹白 晃治, 石原 秀樹, 和泉 究, 市來 淨與, 伊東 宏之, 伊藤 洋介, 井上 開輝, 上田 暁俊, 植田 憲一, 歌島 昌由, 江尻 悠美子, 榎 基宏, 戎崎 俊一, 江里口 良治, 大石 奈緒子, 大河 正志, 大橋 正健, 大原 謙一, 大渕 喜之, 岡田 健志, 岡田 則夫, 河島 信樹, 川添 史子, 河野 功, 木内 建太, 岸本 直子, 國中 均, 國森 裕生, 黒田 和明, 小泉 宏之, 洪 鋒雷, 郡和 範, 穀山 渉, 苔山 圭以子, 古在 由秀, 小嶌 康史, 固武 慶, 小林 史歩, 西條 統之, 齊藤 遼, 坂井 真一郎, 阪上 雅昭, 阪田 紫帆里, 佐合 紀親, 佐々木 節, 佐藤 孝, 柴田 大, 真貝 寿明, 杉山 直, 鈴木 理恵子, 諏訪 雄大, 宗宮 健太郎, 祖谷 元, 高野 忠, 高橋 走, 高橋 慶太郎, 高橋 忠幸, 高橋 弘毅, 高橋 史宜, 高橋 龍一, 高橋 竜太郎, 高森 昭光, 田越 秀行, 田代 寛之, 谷口 敬介, 樽家 篤史, 千葉 剛, 辻川 信二, 常定 芳基, 豊嶋 守生, 鳥居 泰男, 内藤 勲夫, 中尾 憲一, 中澤 知洋, 中須賀 真一, 中野 寛之, 長野 重夫, 中村 康二, 中村 真大, 中山 宜典, 西澤 篤志, 西田 恵里奈, 西山 和孝, 丹羽 佳人, 能見 大河, 橋本 樹明, 端山 和大, 原田 知広, 疋田 渉, 姫本 宣朗, 平林 久, 平松 尚志, 福嶋 美津広, 藤田 龍一, 藤本 眞克, 二間瀬 敏史, 細川 瑞彦, 堀澤 秀之, 前田 恵一, 松原 英雄, 蓑 泰志, 宮川 治, 宮本 雲平, 三代木 伸二, 向山 信治, 武者 満, 森澤 理之, 森本 睦子, 森脇 成典, 八木 絢外, 山川 宏, 山崎 利孝, 山元 一広, 柳 哲文, 横山 順一, 吉田 至順, 吉野 泰造, 若林 野花

    日本物理学会講演概要集65 ( 0 )   2010年

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    記述言語:日本語   出版者・発行元:一般社団法人日本物理学会  

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  • 10aSE-4 スペース重力波アンテナDECIGO計画(20) : 設計・計画(重力波,宇宙線・宇宙物理領域)

    川村 静児, 安東 正樹, 瀬戸 直樹, 佐藤 修一, 中村 卓史, 坪野 公夫, 船木 一幸, 沼田 健司, 神田 展行, 田中 貴浩, 井岡 邦仁, 高島 健, 青柳 巧介, 我妻 一博, 浅田 秀樹, 麻生 洋一, 新井 宏二, 新谷 昌人, 池上 健, 石川 毅彦, 石崎 秀晴, 石徹白 晃治, 石原 秀樹, 市来 浄與, 伊東 宏之, 伊藤 洋介, 井上 開輝, 上田 暁俊, 植田 憲一, 歌島 昌由, 江尻 悠美子, 榎 基宏, 戎崎 俊一, 江里口 良治, 大石 奈緒子, 大河 正志, 大橋 正健, 大原 謙一, 大渕 喜之, 岡田 則夫, 小野里 光司, 河島 信樹, 川添 史子, 河野 功, 木内 建太, 岸本 直子, 國中 均, 國森 裕生, 黒田 和明, 小泉 宏之, 洪鋒 雷, 郡 和範, 穀山 渉, 苔山 圭以子, 古在 由秀, 小嶌 康史, 固 武慶, 小林 史歩, 西條 統之, 齊藤 遼, 坂井 真一郎, 阪上 雅昭, 阪田 紫帆里, 佐合 紀親, 佐々木 節, 佐藤 孝, 柴田 大, 真貝 寿明, 杉山 直, 鈴木 理恵子, 諏訪 雄大, 宗宮 健太郎, 祖谷 元, 高野 忠, 高橋 走, 高橋 慶太郎, 高橋 忠幸, 高橋 弘毅, 高橋 史宜, 高橋 龍一, 高橋 竜太郎, 高森 昭光, 田越 秀行, 田代 寛之, 谷口 敬介, 樽家 篤史, 千葉 剛, 辻川 信二, 常定 芳基, 豊嶋 守生, 鳥居 泰男, 内藤 勲夫, 中尾 憲一, 中澤 知洋, 中須賀 真一, 中野 寛之, 長野 重夫, 中村 康ニ, 中山 宜典, 西澤 篤志, 西田 恵里奈, 西山 和孝, 丹羽 佳人, 能見 大河, 橋本 樹明, 端山 和大, 原田 知広, 疋田 渉, 姫本 宣朗, 平林 久, 平松 尚志, 福嶋 美津広, 藤田 龍一, 藤本 眞克, 二間瀬 敏史, 細川 瑞彦, 堀澤 秀之, 前田 恵一, 松原 英雄, 蓑 泰志, 宮川 治, 三代木 伸二, 向山 信治, 武者 満, 森澤 理之, 森本 睦子, 森脇 成典, 八木 絢外, 山川 宏, 山崎 利孝, 山元 一広, 柳 哲文, 横山 順一, 吉田 至順, 吉野 泰造, 若林 野花

    日本物理学会講演概要集64 ( 0 )   2009年

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    記述言語:日本語   出版者・発行元:一般社団法人日本物理学会  

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  • 30pSC-1 スペース重力波アンテナDECIGO計画(17) : 設計・計画(30pSC 重力波,宇宙線・宇宙物理領域)

    川村 静児, 安東 正樹, 瀬戸 直樹, 佐藤 修一, 船木 一幸, 神田 展行, 中村 卓史, 坪野 公夫, 沼田 健司, 田中 貴浩, 井岡 邦仁, 高島 健, 新谷 昌人, 坂井 真一郎, 中澤 知洋, 長野 重夫, 武者 満, 森脇 成典, 青柳 巧介, 我妻 一博, 浅田 秀樹, 麻生 洋一, 新井 宏二, 池上 健, 石川 毅彦, 石崎 秀晴, 石徹 白晃治, 石原 秀樹, 市來 淨與, 伊東 宏之, 伊藤 洋介, 井上 開輝, 上田 暁俊, 植田 憲一, 歌島 昌由, 江尻 悠美子, 榎 基宏, 戎崎 俊一, 江里口 良治, 大石 奈緒子, 大河 正志, 大橋 正健, 大原 謙一, 大渕 喜之, 岡田 則夫, 小野里 光司, 河島 信樹, 川添 史子, 雁津 克彦, 木内 建太, 岸本 直子, 工藤 秀明, 國中 均, 國森 裕生, 黒田 和明, 小泉 宏之, 洪 鋒雷, 郡 和範, 穀山 渉, 苔山 圭以子, 古在 由秀, 小嶌 康史, 固武 慶, 小林 史歩, 西條 統之, 阪上 雅昭, 阪田 紫帆里, 佐合 紀親, 佐々木 節, 佐藤 孝, 柴田 大, 真貝 寿明, 杉山 直, 鈴木 理恵子, 諏訪 雄大, 宗宮 健太郎, 祖谷 元, 高野 忠, 高橋 走, 高橋 慶太郎, 高橋 忠幸, 高橋 弘毅, 高橋 史宜, 高橋 龍一, 高橋 竜太郎, 高森 昭光, 田越 秀行, 田代 寛之, 谷口 敬介, 樽家 篤史, 千葉 剛, 辻川 信二, 常定 芳基, 豊嶋 守生, 鳥居 泰男, 内藤 勲夫, 中尾 憲一, 中須賀 真一, 中野 寛之, 中村 康二, 中山 宜典, 西澤 篤志, 西田 恵里奈, 西山 和孝, 丹羽 佳人, 能見 大河, 橋本 樹明, 端山 和大, 原田 知広, 疋田 渉, 姫本 宣朗, 平林 久, 平松 尚志, 福嶋 美津広, 藤田 龍一, 藤本 眞克, 二間瀬 敏史, 細川 瑞彦, 堀澤 秀之, 前田 恵一, 松原 英雄, 蓑 泰志, 宮川 治, 三代木 伸二, 向山 信治, 森岡 友子, 森澤 理之, 森本 睦子, 柳 哲文, 山川 宏, 山崎 利孝, 山元 一広, 横山 順一, 吉田 至順, 吉野 泰造, 若林 野花

    日本物理学会講演概要集64 ( 0 )   2009年

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  • Decigo: The japanese space gravitational wave antenna

    Masaki Ando, Seiji Kawamura, Takashi Nakamura, Naoki Seto, Kimio Tsubono, Kenji Numata, Ryuichi Takahashi, Mitsuru Musha, Ken Ichi Ueda, Ikkoh Funaki, Shigenori Moriwaki, Takeshi Takashima, Shin Ichiro Sakai, Takashi Sato, Nobuyuki Kanda, Shigeo Nagano, Mizuhiko Hosokawa, Takehiko Ishikawa, Shuichi Sato, Yoichi Aso, Mutsuko Y. Morimoto, Kazuhiro Agatsuma, Tomomi Akutsu, Tomotada Akutsu, Tomotada Akutsu, Koh Suke Aoyanagi, Koji Arai, Yuta Arase, Akito Araya, Hideki Asada, Takeshi Chiba, Toshikazu Ebisuzaki, Motohiro Enoki, Yoshiharu Eriguchi, Feng Lei Hong, Masa Katsu Fujimoto, Mitsuhiro Fukushima, Toshifumi Futamase, Katsuhiko Ganzu, Tomohiro Harada, Tatsuaki Hashimoto, Kazuhiro Hayama, Wataru Hikida, Yoshiaki Himemoto, Hisashi Hirabayashi, Takashi Hiramatsu, Hideyuki Horisawa, Kiyotomo Ichiki, Takeshi Ikegami, Kaiki T. Inoue, Kunihito Ioka, Koji Ishidoshiro, Hiroyuki Ito, Yousuke Itoh, Shogo Kamagasako, Nobuki Kawashima, Fumiko Kawazoe, Hiroyuki Kirihara, Naoko Kishimoto, Kenta Kiuchi, Werner Klaus, Shiho Kobayashi, Kazunori Kohri, Hiroyuki Koizumi, Yasufumi Kojima, Keiko Kokeyama, Wataru Kokuyama, Kei Kotake, Yoshihide Kozai, Hideaki Kudoh, Hiroo Kunimori, Hitoshi Kuninaka, Kazuaki Kuroda, Kei Ichi Maeda, Hideo Matsuhara, Yasushi Mino, Jun Ichi Miura, Osamu Miyakawa, Shinji Miyoki, Tomoko Morioka, Toshiyuki Morisawa, Shinji Mukohyama, Isao Naito, Noriyasu Nakagawa, Kouji Nakamura, Hiroyuki Nakano, Kenichi Nakao, Shinichi Nakasuka, Yoshinori Nakayama, Erina Nishida, Kazutaka Nishiyama, Atsushi Nishizawa, Yoshito Niwa, Masatake Ohashi, Naoko Ohishi, Masashi Ohkawa, Akira Okutomi, Kouji Onozato, Kenichi Oohara, Norichika Sago

    11th Marcel Grossmann Meeting on Recent Developments in Theoretical and Experimental General Relativity, Gravitation and Relativistic Field Theories - Proc. of the MG11 Meeting on General Relativity   2393 - 2397   2008年12月

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    DECIGO (DECI-hertz interferometer Gravitational wave Observatory) is the future Japanese space gravitational wave antenna with observation band around 0.1 Hz. It aims at detecting gravitational waves from various kinds of sources, with sufficient sensitivity to establish the gravitational wave astronomy. In the pre-conceptual design, DECIGO is formed by three drag-free spacecraft, 1000 km apart from one another. The relative displacements between proof masses housed in these spacecraft are measured by Fabry-Perot interferometers. We plan to launch DECIGO in 2024 after research and development phase, including two milestone missions (DECIGO pathfinder and Pre-DECIGO) for verification of required technologies. © 2008 World Scientific Publishing Co. Pte. Ltd.

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  • 25pZW-6 スペース重力波アンテナDECIGO計画XIII : 設計・計画・パスファインダー(重力波(招待講演),宇宙線・宇宙物理領域)

    安東 正樹, 川村 静児, 中村 卓史, 坪野 公夫, 田中 貴浩, 船木 一幸, 瀬戸 直樹, 沼田 健司, 佐藤 修一, 井岡 邦仁, 神田 履行, 高島 健, 青柳 巧介, 我妻 一博, 阿久津 智忠, 阿久津 朋美, 浅田 秀樹, 麻生 洋一, 新井 宏二, 荒瀬 勇太, 新谷 昌人, 池上 健, 石川 毅彦, 石崎 秀晴, 石徹白 晃治, 石原 秀樹, 市来 淨與, 伊東 宏之, 伊藤 洋介, 井上 開輝, 植田 憲一, 歌島 昌由, 榎 基宏, 戎崎 俊一, 江里口 良治, 大石 奈緒子, 大河 正志, 大橋 正健, 大原 謙一, 奥冨 聡, 小野里 光司, 鎌ヶ迫 将悟, 河島 信樹, 川添 史子, 雁津 克彦, 木内 建太, 岸本 直子, 桐原 裕之, 工藤 秀明, 國中 均, 國森 裕生, 黒田 和明, 小泉 宏之, 洪 鋒雷, 郡 和範, 穀山 渉, 苔山 圭以子, 古在 由秀, 小嶌 康史, 固武 慶, 小林 史歩, 西條 統之, 坂井 真一郎, 阪上 雅昭, 阪田 紫帆里, 佐合 紀親, 佐々木 節, 佐藤 孝, 柴田 大, 真貝 寿明, 杉山 直, 諏訪 雄大, 宗宮 健太郎, 祖谷 元, 高野 忠, 高橋 走, 高橋 慶太郎, 高橋 忠幸, 高橋 弘毅, 高橋 龍一, 高橋 竜太郎, 高森 昭光, 田越 秀行, 田代 寛之, 谷口 敬介, 樽家 篤史, 千葉 剛, 辻川 信二, 常定 芳基, 徳田 充, 徳成 正雄, 豊嶋 守生, 内藤 勲夫, 中尾 憲一, 中川 憲保, 中須賀 真一, 中野 寛之, 長野 重夫, 中村 康二, 中山 宜典, 西澤 篤志, 西田 恵里奈, 西山 和孝, 丹羽 佳人, 橋本 樹明, 端山 和大, 原田 知広, 疋田 渉, 姫本 宣朗, 平林 久, 平松 尚志, 福嶋 美津広, 藤田 龍一, 藤本 眞克, 二間瀬 敏史, 細川 瑞彦, 堀澤 秀之, 前田 恵一, 松原 英雄, 蓑 泰志, 宮川 治, 三代木 伸二, 向山 信治, 武者 満, 森岡 友子, 森澤 理之, 森本 睦子, 森脇 成典, 柳 哲文, 山川 宏, 山崎 利孝, 山元 一広, 横山 順一, 吉田 至順, 吉野 泰造

    日本物理学会講演概要集63 ( 0 )   2008年

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  • 23aSF-1 スペース重力波アンテナDECIGO計画 XV : 設計・計画・パスファインダー(23aSF 重力波,宇宙線・宇宙物理領域)

    安東 正樹, 川村 静児, 瀬戸 直樹, 佐藤 修一, 田中 貴浩, 神田 展行, 船木 一幸, 中村 卓史, 坪野 公夫, 沼田 健司, 高島 健, 井岡 邦仁, 青柳 巧介, 我妻 一博, 浅田 秀樹, 麻生 洋一, 新井 宏二, 新谷 昌人, 池上 健, 石川 毅彦, 石崎 秀晴, 石徹白 晃治, 石原 秀樹, 市來 淨與, 伊東 宏之, 伊藤 洋介, 井上 開輝, 上田 暁俊, 植田 憲一, 歌島 昌由, 江尻 悠美子, 榎基 宏, 戎崎 俊一, 江里口 良治, 大石 奈緒子, 大河 正志, 大橋 正健, 大原 謙一, 小野里 光司, 河島 信樹, 川添 史子, 雁津 克彦, 木内 建太, 岸本 直子, 工藤 秀明, 國中 均, 國森 裕生, 黒田 和明, 小泉 宏之, 洪 鋒雷, 郡和 範, 穀山 渉, 苔山 圭以子, 古在 由秀, 小嶌 康史, 固武 慶, 小林 史歩, 西條 統之, 坂井 真一郎, 阪上 雅昭, 阪田 紫帆里, 佐合 紀親, 佐々木 節, 佐藤 孝, 柴田 大, 真貝 寿明, 杉山 直, 鈴木 理恵子, 諏訪 雄大, 宗宮 健太郎, 祖谷 元, 高野 忠, 高橋 走, 高橋 慶太郎, 高橋 忠幸, 高橋 弘毅, 高橋 史宜, 高橋 龍一, 高橋 竜太郎, 高森 昭光, 田越 秀行, 田代 寛之, 谷口 敬介, 樽家 篤史, 千葉 剛, 辻川 信二, 常定 芳基, 徳田 充, 豊嶋 守生, 鳥居 泰男, 内藤 勲夫, 中尾 憲一, 中澤 知洋, 中須賀 真一, 中野 寛之, 長野 重夫, 中村 康二, 中山 宜典, 西澤 篤志, 西田 恵里奈, 西山 和孝, 丹羽 佳人, 橋本 樹明, 端山 和大, 原田 知広, 疋田 渉, 姫本 宣朗, 平林 久, 平松 尚志, 福嶋 美津広, 藤田 龍一, 藤本 眞克, 二間瀬 敏史, 細川 瑞彦, 堀澤 秀之, 前田 恵一, 松原 英雄, 蓑泰 志, 宮川 治, 三代木 伸二, 向山 信治, 武者 満, 森岡 友子, 森澤 理之, 森本 睦子, 森脇 成典, 柳 哲文, 山川 宏, 山崎 利孝, 山元 一広, 横山 順一, 吉田 至順, 吉野 泰造

    日本物理学会講演概要集63 ( 0 )   2008年

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  • 21aZH-2 スペース重力波アンテナDECIGO計画XII(パスファインダー)(21aZH 重力波,宇宙線・宇宙物理領域)

    安東 正樹, 川村 静児, 瀬戸 直樹, 中村 卓史, 坪野 公夫, 田中 貴浩, 船木 一幸, 沼田 健司, 佐藤 修一, 神田 展行, 高島 健, 井岡 邦仁, 青柳 巧介, 我妻 一博, 阿久津 智忠, 阿久津 朋美, 浅田 秀樹, 麻生 洋一, 新井 宏二, 荒瀬 勇太, 新谷 昌人, 池上 健, 石川 毅彦, 石崎 秀晴, 石徹白 晃治, 石原 秀樹, 市來 淨與, 伊東 宏之, 伊藤 洋介, 井上 開輝, 植田 憲一, 歌島 昌由, 榎 基宏, 戎崎 俊一, 江里口 良治, 大石 奈緒子, 大河 正志, 大橋 正健, 大原 謙一, 奥冨 聡, 小野里 光司, 鎌ヶ迫 将悟, 河島 信樹, 川添 史子, 雁津 克彦, 木内 建太, 岸本 直子, 桐原 裕之, 工藤 秀明, 國中 均, 國森 裕生, 黒田 和明, 小泉 宏之, 洪 鋒雷, 郡 和範, 穀山 渉, 苔山 圭以子, 古在 由秀, 小嶌 康史, 固武 慶, 小林 史歩, 西條 統之, 坂井 真一郎, 阪上 雅昭, 阪田 紫帆里, 佐合 紀親, 佐々木 節, 佐藤 孝, 柴田 大, 真貝 寿明, 杉山 直, 諏訪 雄大, 宗宮 健太郎, 祖谷 元, 高野 忠, 高橋 走, 高橋 慶太郎, 高橋 忠幸, 高橋 弘毅, 高橋 龍一, 高橋 竜太郎, 高森 昭光, 田越 秀行, 田代 寛之, 谷口 敬介, 樽家 篤史, 千葉 剛, 辻川 信二, 常定 芳基, 徳田 充, 徳成 正雄, 豊嶋 守生, 内藤 勲夫, 中尾 憲一, 中川 憲保, 中須賀 真一, 中野 寛之, 長野 重夫, 中村 康二, 中山 宜典, 西澤 篤志, 西田 恵里奈, 西山 和孝, 丹羽 佳人, 橋本 樹明, 端山 和大, 原田 知広, 疋田 渉, 姫本 宣朗, 平林 久, 平松 尚志, 福嶋 美津広, 藤田 龍一, 藤本 眞克, 二間瀬 敏史, 組川 瑞彦, 堀澤 秀之, 前田 恵一, 松原 英雄, 蓑 泰志, 宮川 治, 三代木 伸二, 向山 信治, 武者 満, 森岡 友子, 森澤 理之, 森本 睦子, 森脇 成典, 柳 哲文, 山川 宏, 山崎 利幸, 山元 一広, 横山 順一, 吉田 至順, 吉野 泰造

    日本物理学会講演概要集62 ( 0 )   2007年

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  • 21aZH-3 スペース重力波アンテナDECIGO計画XI(サイエンス)(21aZH 重力波,宇宙線・宇宙物理領域)

    瀬戸 直樹, 川村 静児, 安東 正樹, 中村 卓史, 坪野 公夫, 田中 貴浩, 船木 一幸, 沼田 健司, 佐藤 修一, 神田 展行, 高島 健, 井岡 邦仁, 青柳 巧介, 我妻 一博, 阿久津 智忠, 阿久津 朋美, 浅田 秀樹, 麻生 洋一, 新井 宏二, 荒瀬 勇太, 新谷 昌人, 池上 健, 石川 毅彦, 石崎 秀晴, 石徹白 晃治, 石原 秀樹, 市來 淨與, 伊東 宏之, 伊藤 洋介, 井上 開輝, 植田 憲一, 歌島 昌由, 榎 基宏, 戎崎 俊一, 江里口 良治, 大石 奈緒子, 大河 正志, 大橋 正健, 大原 謙一, 奥冨 聡, 小野里 光司, 鎌ヶ迫 将悟, 河島 信樹, 川添 史子, 雁津 克彦, 木内 建太, 岸本 直子, 桐原 裕之, 工藤 秀明, 國中 均, 國森 裕生, 黒田 和明, 小泉 宏之, 洪 鋒雷, 郡 和範, 穀山 渉, 苔山 圭以子, 古在 由秀, 小嶌 康史, 固武 慶, 小林 史歩, 西條 統之, 坂井 真一郎, 阪上 雅昭, 阪田 紫帆里, 佐合 紀親, 佐々木 節, 佐藤 孝, 柴田 大, 真貝 寿明, 杉山 直, 諏訪 雄大, 宗宮 健太郎, 祖谷 元, 高野 忠, 高橋 走, 高橋 慶太郎, 高橋 忠幸, 高橋 弘毅, 高橋 龍一, 高橋 竜太郎, 高森 昭光, 田越 秀行, 田代 寛之, 谷口 敬介, 樽家 篤史, 千葉 剛, 辻川 信二, 常定 芳基, 徳田 充, 徳成 正雄, 豊嶋 守生, 内藤 勲夫, 中尾 憲一, 中川 憲保, 中須賀 真一, 中野 寛之, 長野 重夫, 中村 康二, 中山 典宜, 西澤 篤志, 西田 恵里奈, 西山 和孝, 丹羽 佳人, 橋本 樹明

    日本物理学会講演概要集62 ( 0 )   2007年

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    日本物理学会講演概要集62 ( 0 )   2007年

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    記述言語:日本語   出版者・発行元:一般社団法人日本物理学会  

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    大河正志

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  • 照明学会論文賞

    2010年9月   照明学会  

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