Noise cleaning of polarization domains in an L-band fiber laser

In this work, we experimentally observed polarization domains underlying cross-gain saturation and gain competition between the polarization modes at orthogonal directions in an L-band fiber laser. We investigated how the background noise of polarization domains be cleaned, which was demonstrated by estimating the polarization instability induced phase difference at orthogonal directions. Noise cleaning occurred when the polarization domains were antiphase. Our work delivers fundamental insights into the polarization instability and the vector beam nonlinear dynamics originating from polarization rotation between orthogonal directions. This work is expected to enrich the laser source optimization scheme by utilizing nonlinear effects to realize noise suppression technology.