Polarization Fading Suppression for Optical Fiber Sensing: A Review

Optical fiber sensors are polarization sensitive and generally affected by polarization fading. This paper contributes to the optimal choice of polarization fading suppression methods for different optical fiber sensors, by means of comparative analysis of the mechanism of polarization fading, the strategy of polarization state control, and the applicability of suppression methods. The comparison results show that the polarization diversity receiving method is suitable for remote multi-channels optical fiber sensing system. The polarization orthogonal pulse pair method is only suitable for optical fiber sensing systems based on the backward scattering light. Meanwhile, the Faraday rotating mirror method is only suitable for optical fiber sensing systems based on the forward light interference. The polarization pulse coding method is suitable for sensing systems with high sensitivity and stability requirements. The polarization control method may increase the control complexity of sensing system for simultaneous variation of multiple polarization states. The full and partial polarization-maintaining fiber methods can be used to keep the polarization state of sensing light along the optical fiber, but the additional system cost limits the application. The polarization scrambler method is currently only available for sensing systems based on Brillouin scattering light. This paper provides a reference for the feasible selection of polarization fading suppression schemes for different optical fiber sensing systems.