Picosecond dynamics of InGaAs microcavity lasers - Influence of carrier transport/capture and gain flattening

We have fabricated and studied the dynamics of In(0.16)G(0.84)As lambda-cavity lasers focusing on the influence of carrier transport/capture and gain flattening by using optical resonant pumping and off-resonant pumping. With the off-resonant pumping, shoulders in the lasing pulse shape were observed, while no shoulder appeared with the on-resonant pumping. By solving the rate equations including carrier transport/capture effects, we reproduced such behavior. Saturation of the inverse rise time was observed at high pump levels. This results from gain flattening due to the step-like density of states of 2D carriers.