Pulse propagation in an elliptically birefringent Kerr medium

The coupled nonlinear Schrodinger equation, which describes optical propagation in a birefringent Kerr medium, is derived with particular emphasis on optical fibers. It is shown that, when the ellipticity angle θ≃35°, Manakov´s equation results. Consequences for switching applications are discussed. In particular, if θ≠35°, shadows form when two pulses of opposite polarization interact, i.e. the emerging pulses no longer have their original polarizations. This problem disappears at θ=35°