Continuous-wave optically pumped 1.55 μm InAs/InAlGaAs quantum dot microdisk lasers epitaxially grown on silicon

Monolithic integration of high-performance semiconductor lasers on silicon enables wafer-scale optical interconnects within photonic integrated circuits on a silicon manufacturing platform. III–V quantum dot (QD) lasers on silicon stand out for their better device performances and reliability. QD lasers grown on III–V substrates have been integrated by wafer-bonding techniques with high quality. Direct growth of QD lasers on silicon offers an alluring alternative, using widely available large-area silicon substrates. However, to date, notable achievements have been reported only in InAs/GaAs lasers emitting at 1.3 μm, while 1.55 μm InAs/InP QD lasers on silicon remain in uncharted territory. Here we demonstrate the first 1.55 μm band InAs/InAlGaAs quantum dot microdisk lasers epitaxially grown on (001) silicon substrates. The lasing threshold for the seven-layer quantum dot microdisk laser at liquid-helium temperature is 1.6 mW under continuous optical pumping. The observed lasing is attributed to a unique combination of the high-quality QDs, small mode volume, and smooth sidewall of the microdisk structure and a well-developed InP buffer incorporating quantum dots as dislocation filters. These results thus mark a major step toward an integrated III–V-on-silicon photonics platform