CARRIER DYNAMICS MODEL OF FAST REFRACTIVE-INDEX CHANGES IN SEMICONDUCTOR-LASER AMPLIFIERS

Recent pump probe measurements of the fast optical response of semicon ductor laser amplifiers are modelled using a density matrix approach i n the relaxation approximation. The results obtained with the model in a variety of situations covering the three regimes below, at and abov e transparency are examined in terms of the optical response and the u nderlying carrier dynamics. The essential features of the optical resp onse are explained using a simple physical picture and good qualitativ e agreement with experiment is demonstrated.