ABSTRACT
This chapter describes the modeling of optical amplifiers that contain semiconductor quantum dots (QDs) as active media. Quantum-dot semiconductor optical amplifiers differ from conventional devices in the choice of active medium. The charge-carrier dynamics in QDs can be very complex due to the localization of electrons within the QDs embedded in the surrounding quantum-well or bulk material. The amplifier active medium is composed of an ensemble of of semiconductor quantum dots. QDs differ from conventional quantum-well or bulk gain media in the presence of localized states and thus a strongly modified density of states. The spontaneous emission created in optical amplifier devices will be subject to stimulated amplification when emitted along the propagation axis. Semiconductor-based optical amplifiers (SOAs) are cheap, relatively easy to fabricate, and consume only little energy within an electric circuit. In linear amplification applications, the device performance of SOAs is generally limited by two competing effects.
