Four-wave mixing of strong picosecond optical pulses in passive semiconductor waveguides

Four-wave mixing (FWM) of strong picosecond optical pulses in passive semiconductor waveguides is investigated numerically, taking into account two-photon absorption (TPA), ultrafast nonlinear refraction, probe depletion, and cross-gain modulation, as well as interband and intraband carrier processes. Simulations show good agreement with published experimental measurements, and indicate that interband and intraband nonlinear mixing and TPA-induced pulse reshaping play significant roles in determining conjugate pulse behaviors for strong pulse energy cases. In particular, for increased pulse energy, an increase in FWM conversion efficiency is predicted, and an optimum pulse width is identified. (C) 1999 American Institute of Physics. [S0003-6951(99)03415-4].