Self-assembled quantum-dot lasers and semiconductor optical amplifiers

Through the research of quantum dot lasers, we have obtained significant knowledge on carrier dynamics and optical gain of quantum dots like homogeneous broadening of single-dot optical gain and its effect on lasing spectra, the magnitude of gain as a function of current, ultrafast gain recovery, and a comprehensive theory. Based on the knowledge, we developed an operation theory of traveling-type quantum-dot semiconductor optical amplifiers (SOAs) to demonstrate that they can process high-bit-rate multiple-wavelength optical signals over 40 Gbit/s under gain saturation. This promises diverse optical functional devices, which meet with the demand of the next-generation broadband all-optical photonic networks