Effect of Free-carrier Absorption on the Carrier Dynamics of Quantum-dot Semiconductor Optical Amplifiers

摘要

The effect of free-carrier absorption on the internal optical loss and the phase recovery dynamics of quantum-dot (QD) semiconductor optical amplifiers (SOAs) is calculated by solving 1088 coupled rate equations and by using the Drude model for free-carrier plasma. The internal optical loss induced by free-carrier absorption is very low, on the order of 0.1 cm(-1), and will not significantly contribute to the total internal loss of QD SOAs. On the other hand, the phase change induced by free-carrier absorption, for which the temporal response is similar to the phase change induced by the interband transitions, contributes to about 50% of the total phase change.