Abstract
We investigate a higher-order nonlinear Schrödinger equation including the intermodal dispersion, self-steepening, delayed nonlinear response effect, and different contributions to the nonlinear dispersion. The model describes ultra-short (femtosecond) optical soliton propagation in metamaterials with Kerr law nonlinearity. By adopting a complex amplitude ansatz composed of the product of bright and dark solitary waves, we present exact dipole soliton solution for the model under certain parametric conditions. This type of soliton pulses characteristically exists due to a balance among nonlinear dispersion effects of different nature. Numerical results and discussions are also presented.