Moving fiber-optic hydrophone

Abstract

A fiber-optic hydrophone based on an intensity-modulation mechanism is described. The device possesses sufficient sensitivity to detect typical deep-sea noise levels in the frequency range 100 Hz to 1 kHz and to detect static displacements of 8.3 × 10−3 Å. It is not susceptible to phase noise and is insensitive to static-pressure head variations. The hydrophone is passive in nature and requires no electrical power. Ease of fabrication and potential low cost make this device an attractive candidate for incorporation into practical fiber-optic acoustic sensing arrays.