Experimental Investigation on a Fibre-Optic Hydrophone with a Cylindrical Helmholtz Resonator

A novel mechanical anti-aliasing filtering fibre-optic hydrophone with a cylindrical Helmholtz resonator is constructed and tested. The experimental results show that the hydrophone has a function of low-pass filtering. The low
frequency acoustic sensitivity is about -160dB (1radμPa), and the response curve has a resonance determined by the Helmholtz resonator. Theoretical and experimental results both show that the resonant frequency moves towards high frequency with the increasing orifice diameters. The sensitivity attenuation of high frequency is larger than 10dB. This new fibre-optic
hydrophone is a prototype device for a class of sensors used to eliminate the aliasing in future sonar systems.