A novel fiber-optic sensor array based on the Sagnac interferometer

We propose a novel design for a fiber-optic acoustic sensor array that is b ased on the Sagnac interferometer. The performance of this Sagnac sensor ar ray (SSA) design is analyzed and compared to acoustic sensor arrays based o n the Mach-Zehnder (MZ) interferometer. It is found that the SSA exhibits s everal decisive advantages, including a stable bias point, a reduced conver sion of source phase noise into intensity noise, and a frequency response t hat matches the ambient ocean noise. It is also shown that the SSA can be e asily designed to have a much larger dynamic range than an MZ-based sensor array. potential noise sources are analyzed and shown to be manageable. A m eans for eliminating polarization-induced signal fading is presented. The a pplicability of time division, frequency-division, and code-division multip lexing schemes for the proposed design is presented.