Variational approach for walking solitons in birefringent fibres

We use the variational method to obtain approximate analytical expressions for the stationary pulse-like solutions in birefringent fibres when differences in both phase velocities and group velocities between the two components and rapidly oscillating terms are taken into account. After checking the validity of the approximation, we study how the soliton pulse shape depends on its velocity and nonlinear propagation constant. By numerically solving the propagation equation we have found that most of these stationary solutions are stable.