Theory of fiber optic lossless polarizers

We present a theoretical description of the light-by-light (nonlinear) polarization control of CW optical beams and short pulses. The present theory only deals with counter-propagating optical beams, for which the effects of group-velocity dispersion (GVD) are typically negligible. Indeed, GVD effects may only slightly modify the performance of lossless polarizers: therefore they are not significant for a basic understanding of the operation of these devices.