Nanowire Lasing With SiN Microring Resonator

We report on-chip room temperature lasing of a nanowire (NW) embedded into a silicon nitride (SiN) microring resonator, where the NW functions as the gain medium whilst the microring provides optical feedback. Owing to the high-quality factor of the hybrid microring, the microring-assisted NW laser exhibits a reduction of lasing threshold to 25.8% and a linewidth narrowing to 11.2% at 1.1 × P_th (lasing threshold), compared to the stand-alone NW laser. Additionally, since the gain medium is only provided by the NW and occupies only a minor portion of the microring resonator, common issues in stand-alone NW lasers, such as wavelength drift and linewidth broadening under increased excitation power, are effectively mitigated. The microring-assisted NW laser offers a viable on-chip light source for SiN photonics, as further demonstrated by coupling the laser output to a bus-waveguide.