Ultra-Thin Optical Hydrophone Array Based On Fiber Bragg Gratings

A 32-elements hydrophone array with diameter of 20mm is obtained based on the FBG-FP(Fiber Bragg Grating Fabry-Perot) interferometer. Multiple FBGs with various wavelength are inscribed on one fiber by continues FBG inscription. Average acoustic pressure sensitivity of hydrophone is -143.9dB re rad/mu Pa, with limited 3dB fluctuation. Intrinsic noise, as crosstalk and polarization induced fading, are restrained by low reflectivity of FBGs to 53dB and eliminated by adding squared signals from three polarization diversity receivers, respectively.