Analysis of Dynamic Switching Behavior of Bistable Semiconductor Ring Lasers Triggered by Resonant Optical Pulse Injection

The relaxation oscillation and decay toward steady state following the switching of the lasing direction in a bistable semiconductor ring laser triggered by resonant optical pulse injection is studied theoretically using small-signal method. Analytical expressions for damping factor, relaxation oscillation frequency, and the decay time are derived. Calculation results based on the expressions derived are compared with numerical simulations, and good agreement is observed. It is shown that the dynamic behavior can be greatly improved by increasing the differential gain, photon density, optical confinement factor, and nonlinear gain compression coefficient, as well as by decreasing the photon lifetime.