Dynamics of an Optically Switched Bistable Semiconductor Laser

The switching time of an optically switched laser diode between a locked mode and free oscillation mode is studied. By starting with linear stability analysis, analytical expressions are developed to predict the switching time. It is shown that the switching of optical output between the locked and unlocked modes is governed by two relaxation processes with different time constants, and the change in the first relaxation process, dependent on the carrier density in the initial state, gives a strong effect on the total switching time, in contrast to the dynamic behavior of the carrier density dominated by a single relaxation process. Our analytical results show that larger detuning and power of optical input are effective in shortening the switching time and are believed useful to estimate the switching time of an optically switched bistable laser diode.