Flywheel-like diaphragm-based fiber-optic Fabry–Perot frequency tailored acoustic sensor

Abstract

Abstract A novel design method for a fiber-optic Fabry–Perot (FP) acoustic sensor based on a flywheel-like diaphragm has been proposed and experimentally demonstrated. Through theory analysis and simulation, we have established a sensing model based on the flywheel-like diaphragm and illustrated the acoustic sensor’s resonant frequency regulation method. A flywheel-like diaphragm-based acoustic sensor has been fabricated and a dual-wavelength system is used to demodulate the phase fluctuation caused by the acoustic wave. Experimental results show that the proposed acoustic sensor has an acoustic pressure sensitivity of 1.3967 rad Pa −1 and noise-limited minimum detectable pressure of ∼ 16.43 μ P a / H z @ 9 k H z . The signal to noise ratio (SNR) of 1 kHz, 9 kHz, and 20 kHz are achieved to be 10.39 dB, 60.51 dB, and 37.14 dB, respectively. Over a fairly broad response range (1 kHz to 20 kHz), the average SNR is up to 45.57 dB. Moreover, our acoustic sensor’s directivity map approximates to a heart shape. Its excellent frequency response characteristics, sensitivity, and directivity pattern are believed to have bright application prospects.