Band gap resonant femtosecond pulse propagation in nonlinear dispersive semiconductor waveguides

A detailed numerical analysis has been made for a femtosecond not-too-stron g Gaussian pulse propagating through a millimeter size GaAs waveguide. The role of weakly bound Is-excitonic structure below the fundamental absorptio n edge has been incorporated in the time dependent perturbation treatment o f the coherent pulse-semiconductor interaction. The analysis reveals the oc currence of both self-steepening and spectral broadening arising due to the inherent intensity dependence of the complex optical susceptibility in GaA s waveguide structures.