Nonlinear repolarization dynamics in optical fibers. transient polarization attraction

In this work, we present a theoretical and experimental study of the response of a lossless polarizer to a signal beam with a time-varying state of polarization (SOP). By lossless polarizer, we mean a nonlinear conservative medium (e.g., an optical fiber) that is counterpumped by an intense and fully polarized pump beam. Such a medium transforms input uniform or random distributions of the SOP of an intense signal beam into output distributions that are tightly localized around a well-defined SOP. We introduce and characterize an important parameter of a lossless polarizer-its response time. Whenever the fluctuations of the SOP of the input signal beam are slower than its response time, a lossless polarizer provides an efficient repolarization of the beam at its output. Otherwise, if input polarization fluctuations are faster than the response time, the polarizer is not able to repolarize light.