Prof. Masashi Ohkawa Profile

Prof. Masashi Ohkawa

Professor at Niigata Univ.

SPIE Involvement:

Author

Publications (66)

Proceedings Article | 2 March 2020 Paper

Frequency characteristics of a semi-closed structure in a guided-wave optical pressure sensor for detection of tsunami formation: investigation based on numerical simulations and experiments

Taiju Triyama, Hana Ono, Naoto Takaoka, Masashi Ohkawa

Proceedings Volume 11274, 112741P (2020) https://doi.org/10.1117/12.2541707

KEYWORDS: Sensors, Protactinium, Numerical simulations, Linear filtering, Prototyping, Polarizers, Waveguides, Polarization, Fluid dynamics, Structural design

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Proceedings Article | 23 October 2018 Paper

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

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

Proceedings Volume 10780, 107801D (2018) https://doi.org/10.1117/12.2324692

KEYWORDS: Semiconductor lasers, Vertical cavity surface emitting lasers, Laser range finders, Fabry–Perot interferometers, Interference (communication), Binary data, Diodes, Oscilloscopes, Laser applications, Analog electronics

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Proceedings Article | 23 October 2018 Paper

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

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

Proceedings Volume 10780, 107800P (2018) https://doi.org/10.1117/12.2324829

KEYWORDS: Distance measurement, Semiconductor lasers, Signal detection, Interference (communication), Absorption, Rubidium, Error analysis, Laser systems engineering, Modulation, Signal generators

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Proceedings Article | 23 February 2018 Paper

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

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

Proceedings Volume 10526, 105260E (2018) https://doi.org/10.1117/12.2288035

KEYWORDS: Semiconductor lasers, Signal detection, Absorption, Laser stabilization, Rubidium, Modulation, Interference (communication), Amplifiers, Signal processing, Neodymium

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Proceedings Article | 23 February 2018 Paper

Fast physical-random number generation using laser diode's frequency noise: influence of frequency discriminator

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

Proceedings Volume 10526, 105261W (2018) https://doi.org/10.1117/12.2288160

KEYWORDS: Vertical cavity surface emitting lasers, Semiconductor lasers, Fabry–Perot interferometers, Oscilloscopes, Binary data, Interference (communication), Avalanche photodetectors, Laser stabilization, Reflectivity, Analog electronics

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Proceedings Article | 23 February 2018 Paper

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

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

Proceedings Volume 10526, 105260W (2018) https://doi.org/10.1117/12.2288086

KEYWORDS: Semiconductor lasers, Distance measurement, Absorption, Interference (communication), Modulation, Signal detection, Rubidium, Laser range finders, Target detection, Laser optics

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Proceedings Article | 19 February 2018 Paper

Evaluation of polymerization and diffusion times in holographic recording for acrylamide-based photopolymer film

Masashi Ohkawa, Keiichi Osabe, Takashi Sato

Proceedings Volume 10558, 1055812 (2018) https://doi.org/10.1117/12.2291122

KEYWORDS: Holography, Diffraction, Polymers, Polymer thin films, Helium neon lasers

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SPIE Journal Paper | 9 June 2017 Open Access

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

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

OE, Vol. 56, Issue 06, 064101, (June 2017) https://doi.org/10.1117/12.10.1117/1.OE.56.6.064101

KEYWORDS: Semiconductor lasers, Frequency modulation, Mirrors, Interference (communication), Fabry–Perot interferometers, Spectral resolution

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SPIE Journal Paper | 22 May 2017

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

Hiroyuki Nikkuni, Masashi Ohkawa, Takashi Sato

OE, Vol. 56, Issue 05, 057108, (May 2017) https://doi.org/10.1117/12.10.1117/1.OE.56.5.057108

KEYWORDS: Sensors, Single mode fibers, Waveguides

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SPIE Journal Paper | 6 January 2016

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

Masashi Ohkawa, Takashi Sato

OE, Vol. 55, Issue 01, 017102, (January 2016) https://doi.org/10.1117/12.10.1117/1.OE.55.1.017102

KEYWORDS: Sensors, Silicon, Optical flow, Waveguides, Silica, Fiber optics sensors, Oxygen, Optical sensors, Polarizers, Optical engineering

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Proceedings Article | 1 September 2015 Paper

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 Volume 9576, 95760N (2015) https://doi.org/10.1117/12.2187963

KEYWORDS: Semiconductor lasers, Distance measurement, Absorption, Modulation, Rubidium, Signal detection, Interference (communication), Oscilloscopes, Laser optics, Semiconductors

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SPIE Journal Paper | 20 February 2013 Open Access

Experimental study of sensitivity dependences on waveguide position and diaphragm thickness in silicon-based guided-wave optical accelerometer

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

OE, Vol. 52, Issue 2, 024604, (February 2013) https://doi.org/10.1117/12.10.1117/1.OE.52.2.024604

KEYWORDS: Waveguides, Sensors, Silicon, Silica, Polarizers, Optical engineering, Mechanical sensors, Interferometers, Etching, Sputter deposition

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SPIE Journal Paper | 7 January 2013 Open Access

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

OE, Vol. 52, Issue 01, 014302, (January 2013) https://doi.org/10.1117/12.10.1117/1.OE.52.1.014302

KEYWORDS: Semiconductor lasers, Absorption, Binary data, Interference (communication), Rubidium, Fabry–Perot interferometers, Optical engineering, Sensors, Signal detection, Optical amplifiers

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Proceedings Article | 29 February 2012 Paper

Fast random-number generation using a diode laser's frequency noise characteristic

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

Proceedings Volume 8255, 825521 (2012) https://doi.org/10.1117/12.908011

KEYWORDS: Semiconductor lasers, Binary data, Diodes, Fabry–Perot interferometers, Interference (communication), Vertical cavity surface emitting lasers, Signal detection, Rubidium, Absorption, Sensors

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Proceedings Article | 29 February 2012 Paper

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

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

Proceedings Volume 8255, 825522 (2012) https://doi.org/10.1117/12.908016

KEYWORDS: Magnetism, Vertical cavity surface emitting lasers, Semiconductor lasers, Monochromators, Fabry–Perot interferometers, Diodes, Mirrors, Spectral resolution, Beam splitters, Avalanche photodetectors

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Proceedings Article | 29 February 2012 Paper

THz wave generation using frequency stabilized laser diodes

Tkashi Sato, Kenji Nakano, Toshiya Nimonji, Masashi Ohkawa, Yasuhito Minamisawa

Proceedings Volume 8255, 82551L (2012) https://doi.org/10.1117/12.908275

KEYWORDS: Terahertz radiation, Absorption, Semiconductor lasers, Fabry–Perot interferometers, Rubidium, Absorption spectroscopy, Laser stabilization, Doppler effect, Signal detection, Gadolinium

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Proceedings Article | 29 February 2012 Paper

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

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

Proceedings Volume 8255, 825529 (2012) https://doi.org/10.1117/12.909622

KEYWORDS: Semiconductor lasers, Vertical cavity surface emitting lasers, Laser stabilization, Optical communications, Singular optics, Telecommunications, Laser optics, Beam splitters, Laser systems engineering, Laser applications

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SPIE Journal Paper | 7 February 2012

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

Masashi Ohkawa, Takashi Sato

OE, Vol. 51, Issue 1, 014401, (February 2012) https://doi.org/10.1117/12.10.1117/1.OE.51.1.014401

KEYWORDS: Sensors, Waveguides, Silicon, Phase measurement, Silica, Polarizers, Optical engineering, Blood pressure, Waveguide sensors, Integrated optics

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Proceedings Article | 2 February 2012 Paper

Evaluation of damping ratio in a glass-based guided-wave optical microphone with a diaphragm

Masashi Ohkawa, Kazuya Murata, Takashi Sato

Proceedings Volume 8264, 82641I (2012) https://doi.org/10.1117/12.910286

KEYWORDS: Waveguides, Magnetic resonance imaging, Acoustics, Polarizers, Glasses, Time metrology, Differential equations, Polarization, Protactinium, Solids

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Proceedings Article | 21 February 2011 Paper

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

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

Proceedings Volume 7933, 79332F (2011) https://doi.org/10.1117/12.875830

KEYWORDS: Semiconductor lasers, Binary data, Interference (communication), Diodes, Absorption, Rubidium, Computer security, Fabry–Perot interferometers, Sensors, Avalanche photodetectors

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Proceedings Article | 21 February 2011 Paper

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

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

Proceedings Volume 7933, 79331O (2011) https://doi.org/10.1117/12.875851

KEYWORDS: Magnetism, Vertical cavity surface emitting lasers, Semiconductor lasers, Monochromators, Diodes, Fabry–Perot interferometers, Mirrors, Avalanche photodetectors, Temperature metrology, Indium arsenide

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Proceedings Article | 17 January 2011 Paper

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

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

Proceedings Volume 7941, 79410P (2011) https://doi.org/10.1117/12.873660

KEYWORDS: Waveguides, Silicon, Sensors, Polarizers, Silica, Integrated optics, Mechanical sensors, Polarization, Etching, Sputter deposition

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Proceedings Article | 26 February 2010 Paper

Physical-random number generation using laser diodes' inherent noises

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

Proceedings Volume 7597, 75970M (2010) https://doi.org/10.1117/12.840626

KEYWORDS: Semiconductor lasers, Binary data, Fermium, Frequency modulation, Laser damage threshold, Fabry–Perot interferometers, Computer security, Interference (communication), Refractive index, Sensors

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Proceedings Article | 26 February 2010 Paper

Frequency stabilization of a laser diode using Rb saturated absorption lines

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

Proceedings Volume 7597, 75971N (2010) https://doi.org/10.1117/12.840610

KEYWORDS: Absorption, Laser stabilization, Rubidium, Semiconductor lasers, Terahertz radiation, Doppler effect, Modulation, Gadolinium, Absorption spectroscopy, Satellites

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Proceedings Article | 26 February 2010 Paper

VCSEL's frequency stabilization of an external cavity diode laser: countermeasures against atmospheric temperature variations

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

Proceedings Volume 7597, 75972A (2010) https://doi.org/10.1117/12.840609

KEYWORDS: Semiconductor lasers, Vertical cavity surface emitting lasers, Laser stabilization, Telecommunications, Optical communications, Signal detection, Fabry–Perot interferometers, Singular optics, Laser systems engineering, Mirrors

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Proceedings Article | 26 February 2010 Paper

Semiconductor laser oscillation-frequency stabilization using the Faraday effect

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

Proceedings Volume 7597, 75971D (2010) https://doi.org/10.1117/12.841526

KEYWORDS: Modulation, Magnetism, Semiconductor lasers, Phase modulation, Signal detection, Absorption, Laser stabilization, Absorption spectroscopy, Satellites, Polarization

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SPIE Journal Paper | 1 January 2010

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

Kohei Doi, Takashi Sato, Masashi Ohkawa

OE, Vol. 49, Issue 01, 014202, (January 2010) https://doi.org/10.1117/12.10.1117/1.3284784

KEYWORDS: Vertical cavity surface emitting lasers, Semiconductor lasers, Mirrors, Singular optics, Telecommunications, Optical engineering, Control systems, Optical communications, Laser optics, Laser stabilization

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SPIE Journal Paper | 1 March 2009

Comparison of three semiconductor laser systems for gravitational wave detection

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

OE, Vol. 48, Issue 03, 034302, (March 2009) https://doi.org/10.1117/12.10.1117/1.3089887

KEYWORDS: Rubidium, Modulation, Semiconductor lasers, Signal detection, Laser stabilization, Magnetism, Absorption spectroscopy, Absorption, Avalanche photodetectors, Laser systems engineering

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Proceedings Article | 24 February 2009 Paper

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

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

Proceedings Volume 7211, 72110A (2009) https://doi.org/10.1117/12.808803

KEYWORDS: Modulation, Semiconductor lasers, Magnetism, Absorption, Laser stabilization, Signal detection, Rubidium, Absorption spectroscopy, Gadolinium, Polarization

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Proceedings Article | 12 July 2008 Paper

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

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

Proceedings Volume 7010, 701047 (2008) https://doi.org/10.1117/12.788681

KEYWORDS: Absorption, Rubidium, Semiconductor lasers, Avalanche photodetectors, Absorption spectroscopy, Laser stabilization, Mirrors, Gadolinium, Signal detection, Diodes

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SPIE Journal Paper | 1 April 2008

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

Hiroyuki Nikkuni, Yu Watanabe, Masashi Ohkawa, Takashi Sato

OE, Vol. 47, Issue 04, 044402, (April 2008) https://doi.org/10.1117/12.10.1117/1.2909669

KEYWORDS: Sensors, Waveguides, Glasses, Silicon, Polarizers, Solids, Optical engineering, Single mode fibers, Polarization, Aluminum

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Proceedings Article | 29 February 2008 Paper

Frequency stabilization of an external cavity diode laser: countermeasures against atmospheric temperature variations

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

Proceedings Volume 6889, 688918 (2008) https://doi.org/10.1117/12.761598

KEYWORDS: Semiconductor lasers, Vertical cavity surface emitting lasers, Laser stabilization, Temperature metrology, Singular optics, Control systems, Fabry–Perot interferometers, Diffraction gratings, Diodes, Optical testing

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Proceedings Article | 22 February 2008 Paper

Semiconductor laser frequency-stabilization: influence of multi-position temperature controls

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

Proceedings Volume 6889, 688917 (2008) https://doi.org/10.1117/12.761595

KEYWORDS: Control systems, Absorption, Rubidium, Semiconductor lasers, Laser stabilization, Gadolinium, Absorption spectroscopy, Signal detection, Doppler effect, Temperature metrology

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Proceedings Article | 24 January 2008 Paper

Analytical discussion of semiconductor lasers for gravitational-wave detection

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

Proceedings Volume 6829, 68291H (2008) https://doi.org/10.1117/12.756222

KEYWORDS: Modulation, Magnetism, Signal detection, Semiconductor lasers, Laser stabilization, Optical filters, Interferometers, Absorption, Optical amplifiers, Polarization

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Proceedings Article | 24 January 2008 Paper

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

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

Proceedings Volume 6829, 68290R (2008) https://doi.org/10.1117/12.756173

KEYWORDS: Rubidium, Absorption, Semiconductor lasers, Laser stabilization, Absorption spectroscopy, Mirrors, Gadolinium, Doppler effect, Signal detection, Chemical species

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Proceedings Article | 22 March 2007 Paper

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

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

Proceedings Volume 6468, 64680D (2007) https://doi.org/10.1117/12.698306

KEYWORDS: Modulation, Semiconductor lasers, Magnetism, Laser stabilization, Signal detection, Absorption, Rubidium, Polarization, Avalanche photodetectors, Satellites

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Proceedings Article | 22 March 2007 Paper

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

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

Proceedings Volume 6468, 64680C (2007) https://doi.org/10.1117/12.698300

KEYWORDS: Semiconductor lasers, Modulation, Absorption, Signal detection, Rubidium, Diodes, Laser stabilization, Absorption spectroscopy, Mirrors, Fabry–Perot interferometers

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Proceedings Article | 22 March 2007 Paper

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

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

Proceedings Volume 6468, 64680E (2007) https://doi.org/10.1117/12.698961

KEYWORDS: Semiconductor lasers, Laser stabilization, Diffraction gratings, Satellites, Laser systems engineering, Singular optics, Laser applications, Telecommunications, Observatories, Reflectors

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Proceedings Article | 9 February 2007 Paper

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

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

Proceedings Volume 6475, 647519 (2007) https://doi.org/10.1117/12.698904

KEYWORDS: Polarizers, Protactinium, Waveguides, Signal to noise ratio, Glasses, Magnetic resonance imaging, Bandpass filters, Photodetectors, Polarization, Interference (communication)

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SPIE Journal Paper | 1 January 2007

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

Keiichi Tsuchida, Masashi Ohkawa, Seishi Sekine

OE, Vol. 46, Issue 01, 015801, (January 2007) https://doi.org/10.1117/12.10.1117/1.2434765

KEYWORDS: Holography, Diffraction, Diffraction gratings, Polymerization, Absorption, Solids, Modulation, Photopolymerization, Refractive index, Optical engineering

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Proceedings Article | 18 October 2006 Paper

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

Seishi Sekine, Takashi Sato, Masashi Ohkawa, Kaoru Sato

Proceedings Volume 6379, 637908 (2006) https://doi.org/10.1117/12.685977

KEYWORDS: Sensors, Linear filtering, Polarizers, Space sensors, Waveguides, Glasses, Integrated optics, Polarization, Data modeling, Environmental sensing

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Proceedings Article | 28 February 2006 Paper

Evaluation of frequency stability in double optical feedback ECDL systems

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

Proceedings Volume 6115, 61150O (2006) https://doi.org/10.1117/12.645759

KEYWORDS: Semiconductor lasers, Rubidium, Laser stabilization, Absorption, Satellites, Laser systems engineering, Active optics, Telecommunications, Singular optics, Interferometers

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Proceedings Article | 28 February 2006 Paper

An investigation into changes observed in the oscillation characteristics of semiconductor lasers exposed to magnetic fields

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

Proceedings Volume 6115, 61150Z (2006) https://doi.org/10.1117/12.645485

KEYWORDS: Magnetism, Semiconductor lasers, Diodes, Resistance, Laser damage threshold, Temperature metrology, Laser optics, Avalanche photodetectors, Spectrum analysis, Beam splitters

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Proceedings Article | 28 February 2006 Paper

Frequency stabilization of laser diode light sources in satellite-to-satellite laser interferometers

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

Proceedings Volume 6115, 611529 (2006) https://doi.org/10.1117/12.645751

KEYWORDS: Modulation, Laser stabilization, Semiconductor lasers, Absorption, Rubidium, Magnetism, Signal detection, Satellites, Interferometers, Absorption spectroscopy

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Proceedings Article | 28 February 2006 Paper

Frequency stabilization of a semiconductor laser using the Rb saturated absorption spectroscopy

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

Proceedings Volume 6115, 61150P (2006) https://doi.org/10.1117/12.645726

KEYWORDS: Absorption, Rubidium, Modulation, Absorption spectroscopy, Laser stabilization, Semiconductor lasers, Signal detection, Chemical species, Doppler effect, Laser beam diagnostics

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Proceedings Article | 27 February 2006 Paper

Stability of holographic gratings recorded on photopolymer using different dyes

Keiichi Tsuchida, Seishi Sekine, Masashi Ohkawa

Proceedings Volume 6136, 613610 (2006) https://doi.org/10.1117/12.645913

KEYWORDS: Diffraction, Holography, Diffraction gratings, Magnesium, Polymerization, Rhodium, Rhodamine B, Helium neon lasers, Mirrors, Polymers

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Proceedings Article | 6 December 2005 Paper

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

Masashi Ohkawa, Takashi Sato, Seishi Sekine, Hiroyuki Nikkuni

Proceedings Volume 6049, 604907 (2005) https://doi.org/10.1117/12.649176

KEYWORDS: Waveguides, Polarizers, Glasses, Protactinium, Magnetic resonance imaging, Sensors, Signal detection, Optical components, Interference (communication), Polarization

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Proceedings Article | 28 April 2005 Paper

Magnetic field effects on semiconductor laser characteristics

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

Proceedings Volume 5722, (2005) https://doi.org/10.1117/12.589744

KEYWORDS: Magnetism, Semiconductor lasers, Diodes, Temperature metrology, Resistance, Spectrum analysis, Avalanche photodetectors, Digital video recorders, Indium arsenide, Optical communications

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Proceedings Article | 21 April 2005 Paper

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

Keiichi Tsuchida, Seishi Sekine, Masashi Ohkawa

Proceedings Volume 5742, (2005) https://doi.org/10.1117/12.588487

KEYWORDS: Diffraction, Holography, Diffraction gratings, Polymerization, Absorption, Refractive index, Modulation, Helium neon lasers, Matrices, Transmittance

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Proceedings Article | 31 March 2005 Paper

Guided-wave optical pressure sensor responding only to changing pressure

Takashi Sato, Seishi Sekine, Masashi Ohkawa, Yoshisumi Endo

Proceedings Volume 5728, (2005) https://doi.org/10.1117/12.588457

KEYWORDS: Sensors, Waveguides, Silicon, Polarizers, Glasses, Objectives, Integrated optics, Helium neon lasers, Space sensors, Ocean optics

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Proceedings Article | 31 March 2005 Paper

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

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

Proceedings Volume 5728, (2005) https://doi.org/10.1117/12.588456

KEYWORDS: Sensors, Silicon, Polarizers, Waveguides, Optical amplifiers, Silica, Magnetic resonance imaging, Protactinium, Polarization, Transducers

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Proceedings Article | 23 March 2005 Paper

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

Takeo Maruyama, Toshiya Nimonji, Ying Li, Hiromichi Kobayashi, Masashi Ohkawa, Shinya Maehara, Shigeo Nagano, Seiji Kawamura, Hiroo Kunimori, Hiroyuki Ito, Taizoh Yoshino, Takashi Sato, Mizuhiko Hosokawa

Proceedings Volume 5710, (2005) https://doi.org/10.1117/12.590396

KEYWORDS: Semiconductor lasers, Laser stabilization, Rubidium, Absorption, Modulation, Magnetism, Signal detection, Satellites, Polarization, Laser optics

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Proceedings Article | 23 March 2005 Paper

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

Masashi Ohkawa, Yuichi Ohta, Tsuneya Tsubokawa, Takashi Sato, Takeo Maruyama, Yoshiharu Kurosaki, Keiki Hasebe, Shinya Maehara

Proceedings Volume 5710, (2005) https://doi.org/10.1117/12.589743

KEYWORDS: Fabry–Perot interferometers, Absorption, Rubidium, Laser stabilization, Semiconductor lasers, Signal detection, Absorption spectroscopy, Chemical species, Control systems, Doppler effect

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Proceedings Article | 20 January 2005 Paper

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

Taizoh Yoshino, Seiji Kawamura, Ying Li, Hiroo Kunimori, Takashi Sato, Mizuhiko Hosokawa, Masashi Ohkawa, Hiromichi Kobayashi, Hiroyuki Ito, Shigeo Nagano, Takeo Maruyama, Shinya Maehara

Proceedings Volume 5628, (2005) https://doi.org/10.1117/12.576544

KEYWORDS: Semiconductor lasers, Laser stabilization, Satellites, Magnetism, Modulation, Rubidium, Absorption, Signal detection, Absorption spectroscopy, Interferometers

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Proceedings Article | 19 June 2003 Paper

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

Masashi Ohkawa, Yoshihiko Iwase, Seishi Sekine, Takashi Sato, Yumi Okamoto

Proceedings Volume 4987, (2003) https://doi.org/10.1117/12.474348

KEYWORDS: Sensors, Waveguides, Integrated optics, Glasses, Polarizers, Silicon, Polarization, Solids, Soda-lime glass, Aluminum

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Proceedings Article | 19 June 2003 Paper

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

Masashi Ohkawa, Seishi Sekine, Toru Tokita, Takashi Sato, Atsushi Yamada

Proceedings Volume 4987, (2003) https://doi.org/10.1117/12.474347

KEYWORDS: Sensors, Waveguides, Integrated optics, Silicon, Phase measurement, Polarizers, Silica, Polarization, Chlorine, Structural sensing

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Proceedings Article | 17 June 2003 Paper

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

Shinichi Ito, Masashi Ohkawa, Takeo Maruyama, Akihiko Sawamura, Takashi Sato, Toshiya Nimonji

Proceedings Volume 4989, (2003) https://doi.org/10.1117/12.474809

KEYWORDS: Magnetism, Laser stabilization, Absorption, Semiconductor lasers, Modulation, Signal detection, Gadolinium, Amplifiers, Polarization, Rubidium

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Proceedings Article | 21 November 2001 Paper

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

Seishi Sekine, Masashi Ohkawa, Takeshi Goto, Atsushi Yamada, Takashi Sato

Proceedings Volume 4591, (2001) https://doi.org/10.1117/12.449164

KEYWORDS: Waveguides, Sensors, Silicon, Integrated optics, Polarizers, Silica, Polarization, Mach-Zehnder interferometers, Resonators, Interferometers

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Proceedings Article | 15 May 2001 Paper

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

Masashi Ohkawa, Yuki Shirai, Takashi Sato, Seishi Sekine, Takeshi Goto

Proceedings Volume 4277, (2001) https://doi.org/10.1117/12.426824

KEYWORDS: Sensors, Waveguides, Integrated optics, Polarizers, Silicon, Silica, Helium neon lasers, Polarization, Blood pressure, Optical circuits

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Proceedings Article | 29 March 2000 Paper

Oscillation wavelength shifts of laser diodes with or without a package in a magnetic field

Akinori Nishiie, Minoru Shimba, Takashi Sato, Takeo Maruyama, Yasuaki Ohsawa, Takayuki Nakagawa, Masashi Ohkawa

Proceedings Volume 3945, (2000) https://doi.org/10.1117/12.380539

KEYWORDS: Magnetism, Semiconductor lasers, Temperature metrology, Diodes, Packaging, Spectrum analysis, Digital video recorders, Resistance, Magnetic semiconductors, Ferromagnetics

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Proceedings Article | 24 March 2000 Paper

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

Kazuhiko Hasebe, Seishi Sekine, Chikara Nishiwaki, Takashi Sato, Masashi Ohkawa

Proceedings Volume 3936, (2000) https://doi.org/10.1117/12.379963

KEYWORDS: Sensors, Waveguides, Interferometers, Glasses, Integrated optics, Polarizers, Mach-Zehnder interferometers, Polarization, Wave sensors, Waveguide sensors

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Proceedings Article | 7 May 1999 Paper

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

Kazuhiko Hasebe, Masashi Ohkawa, Takashi Sato, Seishi Sekine, Chikara Nishiwaki

Proceedings Volume 3740, (1999) https://doi.org/10.1117/12.347732

KEYWORDS: Sensors, Waveguides, Glasses, Integrated optics, Polarizers, Photoelasticity, Interferometry, Polarization, Ultraviolet radiation, Helium neon lasers

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Proceedings Article | 8 October 1998 Paper

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

Masashi Ohkawa, Kazuto Tamura, Minoru Shimba, Kuniyuki Hosoya, Takeo Maruyama, Takashi Sato, Hiroki Nakamura, Hiroyuki Nakano

Proceedings Volume 3415, (1998) https://doi.org/10.1117/12.326633

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Proceedings Article | 8 October 1998 Paper

Oscillation frequency stabilization of a semiconductor laser using the magneto-optical effects of Rb-D2 absorption line

Masashi Ohkawa, Kunihiro Ishikawa, Takashi Sato, Toshiya Nimonji, Takeo Maruyama, Hiroyuki Nakano, Minoru Shimba, Hitoshi Nakamura

Proceedings Volume 3415, (1998) https://doi.org/10.1117/12.326635

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Proceedings Article | 8 October 1998 Paper

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

Takayuki Nakagawa, Hiroyuki Nakano, Kouichi Matsumoto, Takashi Sato, Minoru Shimba, Takeo Maruyama, Masashi Ohkawa, Shin-ya Toujou

Proceedings Volume 3415, (1998) https://doi.org/10.1117/12.326632

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Proceedings Article | 1 June 1994 Paper

Oscillation wavelength shifts of diode lasers in a magnetic field

Minoru Shimba, Shigeki Yamamoto, Hidetoshi Kawashima, Tomoya Hoshi, Takeo Maruyama, Masashi Ohkawa, Takashi Sato

Proceedings Volume 2148, (1994) https://doi.org/10.1117/12.176640

KEYWORDS: Semiconductor lasers, Magnetism, Absorption, Laser damage threshold, Temperature metrology, Monochromators, Fabry–Perot interferometers, Chemical oxygen iodine lasers, Communication engineering, Electrical engineering

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Showing 5 of 66 publications

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