Carrier heating in InGaAsP laser amplifiers due to two-photon absorption

The carrier dynamics in an InGaAsP quantum-well laser amplifier excited by an ultrashort optical pulse is investigated experimentally as well as theoretically. For operation in the absorption region, a transition from pump induced cooling to pump induced heating of the carriers is observed for increasing pump pulse energy and is attributed to the generation of hot carriers through two-photon absorption. The results further support the interpretation of the carrier dynamics in the perturbative regime.