Nonlinear evolutions with singular dispersion laws associated with a quadratic bundle

Abstract

We obtain a hierarchy of nonlinear evolution equations with self-consistent source related to the Wadati-Konno-Ichikawa type spectral problem. The modified NLS equation with a source, which describes the ultrashort light pulse propagation in a nonlinear single-mode optical fiber with resonant impurities, is shown to be a gauge-transformed member of the hierarchy. The soliton solution for this equation is found. © 1995.