Linewidth Enhancement Factor in InAs/GaAs Quantum Dot Lasers and Its Implication in Isolator-Free and Narrow Linewidth Applications

Abstract

The linewidth enhancement factor (alpha -mathrmH) is an important parameter for semiconductor lasers. In this paper, we investigate, both theoretically and experimentally, the key parameters that affect alpha -mathrmH of InAs/GaAs quantum dot lasers. Both dot uniformity and doping density are found to be critical in achieving small alpha -mathrmH in quantum dot lasers. The prospects for quantum dot lasers in isolator-free and narrow linewidth applications are also discussed.