High-sensitivity FBG microphone with static pressure equalization and optimized response

• 来源期刊: 中国光学快报（英文版）
• 年，卷（期）: 2019,（1）
• 页码范围: 5-9
• 页数: 5页
• 语种: 英文
• DOI: 10.3788/COL201917.010601

摘要

We present a high-sensitivity fiber Bragg grating (FBG)-based microphone with a flat response and static pressure equalization.A very high dynamic sensitivity of the microphone is achieved by a pressure sensing structure based on a carbon fiber diaphragm.Static pressure equalization is realized by a balance structure with a capillary glass tube.The resonances of the sensor are suppressed by air damping structures,and a broadened fiat response is achieved.An acoustic-solid interaction model was used to analyze the response characteristics of the microphone.An experimental prototype was produced and tested,and the results are well consistent with the design.The tested sensitivity was-10 dB re 1 pm/Pa from 10 Hz to 2.5 kHz with a fluctuation of less than ±1.5 dB.Combined with the phase-generated-carrier-based coherent detection scheme,the microphone can achieve a sound resolution of the milli-pascal level.The static pressure sensitivity is measured to be-0.27 pm/atm,which is 100 dB lower than the dynamic sensitivity.