Nonlinear pulse propagation in a monomode dielectric guide.

We derive the nonlinear wave equation for an envelope of an electromagnetic wave in a mono-mode dielectric wave guide. Concrete examples are given for a single mode optical fiber where the coefficients of resultant nonlinear Schrodinger equation with higher order dispersion (both linear and nonlinear) are given in terms of properties of the eigenfunction of the guided wave as well as of the material nonlinearity and dispersion. We also present a perturbation method of solutions to the perturbed nonlinear Schrodinger equation. The higher order dispersions are shown to preserve the profile of a single soliton but to split up a bound N-soliton (N >=2) into individual solitons with different heights which propagate at different velocities.