Differential gain and gain compression of an overdamped interband cascade laser

This work investigates the differential gain and gain compression factor of an interband cascade laser (ICL), through the analysis of the small-signal modulation response. The differential gain of the ICL is extracted to be 7.9 × 10−16 cm2, which is comparable to that of typical quantum well lasers. On the other hand, the gain compression factor is determined to be 5.1 × 10−15 cm3, which is two orders of magnitude higher than the latter. In addition, we demonstrate that the ICL is overdamped due to the strong gain compression effect. It is found that the K factor governed by the damping factor and the resonance frequency is as high as 31.4 ns.