Novel fiber optic sensor array based on the Sagnac interferometer

We present a novel concept for an acoustic fiber sensor array based on the Sagnac interferometer. Its characteristics and performance are analyzed theoretically and shown to be superior in several important areas to standard sensor arrays based on Mach-Zehnder (MZ) interferometers. In particular, the Sagnac sensor array (SSA) exhibits a stable bias point, a reduced conversion of source phase noise into intensity noise, a frequency response matched to the ambient ocean noise (of relevance for underwater acoustic sensing), and freedom from polarization-induced signal fading. The dynamic range of the SSA can also be easily designed to far exceed the dynamic range of a MZSA.

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