Time-dependent simulation of a semiconductor laser amplifier: pulse compression in a ring configuration and dynamic optical bistability

A dynamic theory for a semiconductor laser amplifier with time-dependent optical input signal and driving injection current is presented. Previous treatments are extended by including a carrier density-dependent refractive index, a frequency-dependent gain, and multimode operation. The simulation yields optical bi- and tristability strongly depending on the speed at which the optical input-output characteristic is scanned. Tristability can be found in case of high pumping and large linewidth enhancement factor only. Applying the theory to a ring laser configuration, asymptotic pulse compression, which can lead to the emission of a stable sequence of short pulses with widths down to about 6 ps is found