Line of polarization attraction in highly birefringent optical fibers

We investigate the phenomenon of polarization attraction in a highly birefringent fiber. This polarization process originates from the nonlinear interaction of two counter-propagating beams. We show that all polarization states of the forward (signal) beam are attracted toward a specific line of polarization states on the surface of the Poincaré sphere, whose characteristics are determined by the polarization state of the injected backward (pump) beam. This phenomenon of polarization attraction takes place without any loss of energy for the signal beam. The stability of different stationary solutions is also discussed through intensive numerical simulations. On the basis of mathematical techniques recently developed for the study of Hamiltonian singularities, we provide a detailed description of this spontaneous polarization process. In several particular cases of interest, the equation of the line of polarization attraction on the Poincaré sphere can be obtained in explicit analytical form.