Carrier DC and AC capture and escape times in quantum-well lasers

A theoretical model is proposed to study the carrier DC and AC capture and escape times in the small signal modulation response of quantum-well lasers. We derive the DC and AC capture and escape times by calculating the carrier net capture current. Our numerical results indicate that the AC capture and escape times are smaller than the DC capture and escape times. In some cases, they may be even smaller by one order of magnitude. We also find that the AC capture/escape time ratio is larger than the DC capture/escape time ratio by a factor of two. Therefore, conventional theoretical models that do not distinguish the differences between the DC and AC capture and escape times may overestimate the resonant frequency and underestimate the damping rate in the modulation response of quantum-well lasers, i.e., the AC capture and escape times limit the modulation bandwidth of quantum-well lasers more severely than that predicted by the DC capture and escape times.<>