Depolarization of light due to the optical Kerr effect in low-birefringence single-mode fibers

The evolution of the state of polarization of an electromagnetic field propagating in a low-birefringence single-mode fiber in the presence of the nonlinear interaction associated with the optical Kerr effect is investigated. We explicitly evaluate the degree of polarization P(z) as a function of the fiber length z for a completely polarized input field [P(0) = 1] possessing an exponential intensity distribution, such as the one furnished by a multimode laser. Furthermore, the asymptotic value P(∞) corresponding to an arbitrary distribution of the input intensity is determined.