Monte Carlo simulation of gain compression effects in GRINSCH quantum well laser structures

Gain compression is widely acknowledged to be a serious limitation to the ultimate modulation bandwidth of a semiconductor laser. We have developed a numerical technique to study the gain compression effects in graded-index separate confinement heterostructure (GRINSCH) quantum well laser structures, This technique is based on the combination of the Monte Carlo simulation of the carrier dynamics in the device while under intense stimulated photon emission, and the calculation of the optical gain using a 4×4 k·p Hamiltonian. From the simulated results, we calculated a gain compression coefficient ε=1.1×10^-17 cm³ for a linearly graded quantum well laser structure having a 50 Å In_0.2Ga_0.8As well. We find good agreement between our results and published experiments. We have also demonstrated that our calculation method is capable of simulating the gain dynamics in the laser structure, such as those studied with femtosecond pump-probe experimental techniques