Effect of well-barrier hole burning on the dynamic response of quantum-well lasers

A rate-equation model of quantum-well lasers is presented which includes the effects of transport and partitioning of carriers between Ihe well and confinement layers. The predictions of this model are shown to be consistent with measurements of the structure-dependent reduction of the high-frequency response of these lasers. The implications of this model for the design of high-frequency quantum-well lasers is discussed. If their frequency response is not limited by electrical (AC) parasitics, or by heat generated at high power, the maximum modulation bandwidth of bulk semiconductor lasers is intrinsically limited to between about 25-45 GHz by damping due to nonlinear gain [1]. In addition to the limitations imposed by nonlinear gain, it has recently been shown [2] that the maximum modulation bandwidth of quantum-well lasers can under certain circumstances be severely reduced (< 1 0 GHz) by processes associated with their structure. The physical mechanisms responsible for these structure-dependent processes are the same as those which have been proposed to govern the gain recovery dynamics of quantum-well amplifiers [3]. In this paper, the "well-barrier hole burning" model [4] of quantum-well lasers is described. The results of measurements which are consistent with the model are presented. Finally, the implications of this model for the design of high-frequency quantum-well lasers are discussed.