Polarization fading suppression in distributed interferometric sensing by matched interference between polarization-switched pulses

Abstract

A polarization fading suppression technique is proposed for distributed interferometric sensing systems, based on matched interference between polarization switched pulses. For each individual sensor, two sets of interferometric outputs are obtained, one corresponding to the interference between two pulses with initially parallel polarization, the other corresponding to that between two pulses with initially orthogonal polarizations. As such, at least one output presents visibility no less than 2 / 2 . By selecting the one with higher visibility for demodulation, the influence of polarization fading can be suppressed significantly, leading to distributed acoustic sensing with notably improved robustness and reliability.

The Impact of Rayleigh Scattering in UWFBG Array-Based Φ-OTDR and Its Suppression Method

“…Polarization fading noise is another issue that can seriously diminish the visibility of the beat signal within the UWFBG array. Xuelei Fu et al proposed a technique based on matched interference between polarization-switched pulses, which effectively suppresses the effect of polarization fading [22].…”