Perturbed solitons in birefringent fibres

A perturbation theory based on inverse scattering theory is developed for the coupled nonlinear Schroedinger equations. The theory finds useful application to the study of pulse propagation down a birefringent optical fibre and is used to examine features of the radiation field shed by a soliton pulse propagating down the fibre. The radiation field is linked to the scattering data through a transform pair which in the linear limit reduces to the forward and inverse Fourier transform pair. A complementary approach, which is in total agreement to these results, is also discussed