Gain and carrier temperature response of semiconductor laser media to short optical pulses

摘要

The gain and carrier temperature response of semiconductor laser media to picosecond optical pulses with various pulse energies is obtained by means of a model that is based on rate equations extended to include the carrier energy density equation. The temperature dynamics are obtained from the carrier energy density by use of a quasi-equilibrium Fermi-Dirac distribution. We study the cases of media whose prepulse states are strongly absorbing, transparent, and strongly amplifying at the frequency of the pulse. The results show that the various physical processes that influence the gain and carrier temperature contribute differently, depending on both the initial state of the medium and the pulse energy. In particular, the influence of free-carrier absorption and two-photon absorption on the dynamics of the carrier temperature and the gain coefficient is discussed in detail. (C) 2000 Optical Society of America [S0740-3224(00)01305-9]. OCIS codes: 320.0320, 320.5390, 320.7130, 250.5980, 190.5970, 190.4720, 140.5960. [References: 41]