High-frequency interferometric optical fiber hydrophone based on acoustic resonance isolation

We propose and demonstrate a high-frequency interferometric optical fiber hydrophone based on acoustic resonance isolation. Novel air chambers are introduced into common type of mandrel sensitization structure to prevent acoustic resonance which occurs inside the inner cylindrical cavity of hydrophone frame at specific high frequency acoustic filed. 1kHz-30kHz frequency response of this new kind of hydrophone is measured in a lake. Experiment shows that, by this acoustic structure optimization, the working frequency bandwidth of optical fiber hydrophone, whose acoustic pressure sensitivity is-147dB, is expanded from 10kHz to above 30kHz.