HOT-CARRIER AND HOT PHONON EFFECTS ON HIGH-SPEED QUANTUM-WELL LASERS

We present a theoretical model to analyze the hot carrier and hot phon on effect on the modulation response of semiconductor quantum well las ers. We find that the carrier heating strongly depends on the energy r elaxation time of carriers and the lifetime of longitudinal-optic (LO) phonons. Furthermore, the carrier heating will significantly decrease the differential gain and increase the nonlinear gain coefficient and thus reduce the modulation bandwidth. From the numerical result, we d emonstrate the bottleneck effect of the hot LO phonons on the modulati on response of quantum well lasers. This implies that reducing the lif etime of LO phonons, for example, by doping in the quantum well, will most effectively decrease the carrier temperature and thus improve the modulation bandwidth.