A perturbed nonlinear Schrödinger equation that describes femtosecond pulse propagation in spatially (axially) inhomogeneous optical fibers near the zero-dispersion point is considered. This equation, which has varying coefficients, is analyzed by means of a multiple-scale perturbation technique. Approximate analytical results, valid up to the first order, concerning both the envelope function and the carrier wave number and frequency, are derived. Necessary conditions for envelope bright solitary-wave formation, as well as the solutions themselves, are presented. Typical results concerning the effect of the inhomogeneity on the solitary-wave propagation also are given.
© 1995 Optical Society of America
D. J. Frantzeskakis, E. Papaioannou, and K. Hizanidis, "Slowly varying femtosecond solitary waves in axially inhomogeneous optical fibers near the zero-dispersion point," J. Opt. Soc. Am. B 12, 1671-1679 (1995)