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.