Dark soliton solutions of the coupled Hirota equation in nonlinear fiber

We consider the coupled Hirota equation which describes the pulse propagati on in a coupled fiber with higher-order dispersion and self-steepening. Usi ng the Painleve analysis, we obtain the parametric conditions for the exist ence of bright and dark solitons. For the identified case(s), we also const ruct the common Lax pair and the soliton solutions are constructed for the dark soliton case. Also we extend our results to N-field propagation and th e explicit Lax pair is constructed. (C) 2001 Elsevier Science B.V. All righ ts reserved.