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A control method to eliminate polarization-induced Phase distortion in dual Mach-Zehnder fiber interferometer

Polarization-induced Phase distortion happens in the distributed dual Mach-Zehnder fiber interferometric sensing system, which results in big locating errors. Based on the investigation in the cause, we propose and demonstrate a scheme using automatic polarization controller together with simulated annealing as control algorithm to obtain high positioning accuracy in the system. Through laboratory experiments, the key parameters of the algorithm are analyzed and the optimal settings of them are fixed. Field trial results show that this method can make a fast search for the optimal state of polarization and maintain the strong signal correlation for a long time.