Time-domain large-signal investigation on nonlinear interactions between an optical pulse and semiconductor waveguides

A time-domain large-signal model is developed to investigate nonlinear interactions between picosecond optical pulses and semiconductor active waveguide devices, including distributed-feedback and Fabry-Perot lasers, as well as optical amplifiers. The model predicts interesting phenomena such as transform-limited superluminal transmission and directional DFB amplification. The influence of electrical carrier dynamics and feedback from a Bragg grating and/or reflecting facets on output pulses are demonstrated. Moreover, it is found that the time delay of the reflected and transmitted pulses is strongly related to the Bragg grating parameters, as well as to carrier dynamics. As a consequence, careful attention should be paid when the notions of group refractive index and group velocity are to be used in device modeling.