Linewidth narrowing in self-injection-locked, on-chip lasers

On-chip laser diodes based on quantum well (QW) and quantum dot (QD) semiconductor materials have become the primary technology for several applications due to their excellent characteristics, including high power efficiency, high-temperature operation, and small form-factors. Although QWs have been extensively used in commercial products, QDs have emerged as an attractive alternative due to their unique zero-dimensional density of states and atom-like degeneracy.