Broad-band gain incorporating quantum dot fluctuations for a GaInNAs semiconductor optical amplifier

It has been observed experimentally that the band edge photoluminescence (PL) of Ga_xIn_1-xN_yAs_1-y Quantum Well (QW) materials is broadened. This has been attributed to compositional fluctuations of the N. These fluctuations can be modelled as quantum dot-like fluctuations in the conduction band edge of the GaInNAs/GaAs QW. We have developed a rate-equation approach to evaluate the distribution of electrons in the QW energy level and the QD-like fluctuations which includes carrier recombination from both the conventional 2D QW layer and the inhomogeneous dot-like fluctuations. The electron dynamics in the QW and QDs states are examined and the resulting carrier population and broad band gain is derived for a single QW. This is then applied to the design of a broad band gain semiconductor optical amplifier (SOA).