Polarization Attraction in Counterpropagating Fiber Raman Amplifiers

Polarization attraction in counterpropagating, randomly birefringent, fiber Raman amplifiers is numerically investigated, including the effects of nonlinear polarization rotation, pump depletion and orthogonal Raman gain. The analysis determines the limitations of the pulling efficiency, and shows that the maximum achievable mean degree of polarization is a function of the mean gain.