An Improved Polarization Compensation Method for Interferometric Fiber-Optic Intrusion Sensors

In this letter, we proposed an improved polarization compensation method to eliminate polarization-induced phase shift and polarization-induced fading and enhance the positioning accuracy of interferometric fiber-optic intrusion sensor based on dual Mach-Zehnder interferometry. The implement scheme employs two polarization controllers (PC) to compensate the polarizations of light beams before they interfere at beam combiner. The compensation strategy of optimum polarization adjustment is based on the directed compensation of the state of polarization (SOP) and it has the advantages of fast PC adjustment and fine synchronization of the interference light beams. We also experimentally demonstrated the efficiency of our proposed method with a positioning error within +/- 30 m.