Optical gain in InGaAs/GaAs self-assembled quantum dots and its effect on optical devices

This paper presents theoretical and experimental studies on the optical gain of self-assembled InGaAs/GaAs quantum dots: 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 results, we developed an operation theory of traveling-type quantum-dot semiconductor optical amplifiers 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 next-generation broadband all-optical photonic networks.