Subpicosecond pulse amplification in semiconductor laser amplifiers

Recent experimental progress in high power modelocked semiconductor lasers together with the discovery of subpicosecond time scale gain and index dynamics in semiconductor amplifiers has underscored the need for an improved theory of amplification in these devices that correctly accounts for TeraHertz bandwidths and high intensities. The authors present an improved and more general version of their theoretical model for femtosecond pulse amplification in a SLA that includes the influence of finite intraband relaxations time. Comparison of calculation with a sequence of experiments on an angle stripe geometry SLA show excellent agreement and give parameter values that are all reasonable and also give information on the underlying physics. The propagation of the pulse in the SLA is described by a nonlinear equation for the time domain pulse envelope which includes both intensity and phase shaping effects as well the rapid gain and phase dynamics which have been observed through pump-probe experiments