Low-noise monolithic mode-locked semiconductor lasers through low- dimensional structures

摘要

The design of a quantum well (QW) based high-saturation energy and low-loss gain region allows a high power density which ensures efficient saturation of the absorber, increases the efficiency, and lowers the noise of monolithic mode-locked lasers. This is illustrated though 10 GHz all-active lasers with different number of quantum wells. By comparing a 40 GHz quantum dot and a 40 GHz quantum well laser we discuss the physical difference in the dynamics of the devices. The slow dynamics of quantum dots (QD), results in low self-phase modulation for picosecond pulses and a strong damping of intensity fluctuations, which gives rise to clean optical spectra and very low noise for passive mode-locking.