Quantum dot photonic devices for lightwave communications

Semiconductor quantum dots (QDs) have appealed to physicists and engineers since many years due to their ultimate carrier confinement. The new, realistic models of quantum dot lasers close to reality are based on strained heterostructures, finite barriers, many electron and hole levels, monomolecular (excitonic) recombination and non-equilibrium carrier distribution. The use of GaAs-based QDs in diode lasers and amplifiers at telecom wavelengths has been demonstrated to yield a large number of decisive advantages for systems, both from point of view of performance and of cost. For future metropolitan area networks the demand for inexpensive ultrafast amplifier is probably larger that of lasers. Semiconductor optical amplifiers (SOAs) are expected to play a decisive role here.