Ultra-fine cable fiber optic hydrophone array for acoustic detection

Abstract

We demonstrate an ultra-fine fiber optic hydrophone array for acoustic detection. It is consisted of Weak Reflection Fiber Bragg Grating (WFBG), including four layers: optical fiber layer, coating layer, tensile layer, and sealing layer. Moreover, an hydroacoustic detection system which based on matched interference is established. The responses of underwater acoustic signals, generated by vibration liquid column, in the areas of amplitude, phase and frequency were demodulated simultaneously using the combining algorithm of digital arc tangent and PGC algorithm. A relative flatness response of 3dB was achieved in the frequency range from 200 to 2000 Hz. And the experiments showed that acoustic pressure sensitivity is about -147.96 dB (re 1rad/μPa).