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2 February 2009 An FBG-based optical microphone with temperature insensitivity
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A fiber optical microphone with temperature insensitivity is described in this paper. A sensor system achieves acoustic vibration signal by attaching a Fiber Bragg Grating (FBG) to a diaphragm which can response to acoustic vibrations. Broadband light is launched into the FBG through a coupler and the light reflected by the FBG is directed to another matched FBG which works as a wavelength demodulator. Vibration of the diaphragm causes stress changes to the FBG, and introduces variations of the FBG wavelength. Therefore, acoustic vibrations can be detected by measuring the FBG wavelength variations. In this study, a pair of matched FBGs is employed for both wavelength demodulation and temperature compensation. These features not only make the fiber optical microphone achieve a stable operation, but also improve the entire frequency range of demodulation. Compared with traditional microphones, the fiber optical microphone can achieve low noise and a superior performance of anti-electromagnetic interference.
© (2009) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Danying Zheng, Qun Liu, and Enbang Li "An FBG-based optical microphone with temperature insensitivity", Proc. SPIE 7157, 2008 International Conference on Optical Instruments and Technology: Advanced Sensor Technologies and Applications, 71570U (2 February 2009);

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