SLOWLY VARYING FEMTOSECOND SOLITARY WAVES IN AXIALLY INHOMOGENEOUS OPTICAL FIBERS NEAR THE ZERO-DISPERSION POINT

A perturbed nonlinear Schrodinger 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 pertur bation technique. Approximate analytical results, valid up to the firs t order, concerning both the envelope function and the carrier wave nu mber and frequency, are derived. Necessary conditions for envelope bri ght solitary-wave formation, as well as the solutions Typical results concerning the effect of the inhomogeneity on the solitary-wave propag ation also are given. (C) 1995 Optical Society of America