| Project/Area Number |
11695039
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Applied optics/Quantum optical engineering
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| Research Institution | GUNMA UNIVERSITY |
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Principal Investigator |
YOSHINO Toshihiko Gunma University, Faculty of Engineering, Professor, 工学部, 教授 (90013169)
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| Co-Investigator(Kenkyū-buntansha) |
YOKOTA Masayuki Gunma University, Faculty of Engineering, Research Associate, 工学部, 助手 (80323335)
TAKAHASHI Yoshitaka Gunma University, Faculty of Engineering, Associate Professor, 工学部, 助教授 (30216767)
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| Project Period (FY) |
1999 – 2001
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| Project Status |
Completed (Fiscal Year 2001)
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| Budget Amount *help |
¥2,200,000 (Direct Cost: ¥2,200,000)
Fiscal Year 2001: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 2000: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 1999: ¥800,000 (Direct Cost: ¥800,000)
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| Keywords | Optical Fiber / Distributed Sensor / Fiber Interferometer / Temperature Measurement / Brillouin Scattering / ブリュアン散乱 / 温度測定 / 歪測定 / 歪み測定 |
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| Research Abstract |
A simultaneous temperature and strain measurement system based on spontaneous Brillouin scattering has been proposed and analyzed theoretically and experimentally, which uses a fiber double-pass Mach-Zehnder interferometer to separate the Brillouin signal from Rayleigh scattering and uses a single-pass Mach-Zehnder interferometer to transform the Brillouin frequency shift change due to temperature and stain along the sensing fiber into intensity variation and utilizes processing of the two output signals of the single-pass Mach-Zehnder interferometer to get the distributed information of temperature and strain along the fiber and to shorten the measurement time. A fiber double-pass Mach-Zehnder interferometer with an insertion loss of less than 2.5 dB and a rejection of Rayleigh scattering over 30 dB has been developed and used in the high temperature sensing system. Dependence of Brillouin scattering intensity in a dispersion-shifted fiber on temperature had been measured in time domain in a temperature range 18 ℃ to 722 ℃ when the temperature was increased and decreased, respectively. It has been made clear that distortion of the fiber coating with the temperature increase causes mirobending of the fiber and attenuates Brillouin scattering intensity greatly in the range 450 ℃ to 520 ℃, but as the temperature is decreased to ambient temperature Brillouin scattering intensity varies with temperature decrease linearly by a coefficient of (0.26 0.04) %/℃ since the fiber coating has been burned almost totally. High temperature measurement in the range 18 ℃ to 722 ℃ has been realized with a spatial resolution of 13 m at the far end of a 4 km long dispersion-shifted fiber.
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