Abstract
The dynamics of dark solitons is studied within the framework of a generalized nonlinear Schrodinger equation. The specific cases of parabolic law and dual-power law nonlinearity are considered. The solitary wave ansatz method is used to carry out the integration. All the physical parameters in the soliton solutions are obtained as functions of the dependent model coefficients. Parametric conditions for the existence of envelope solitons are given. Copyright (C) 2011 John Wiley & Sons, Ltd.