Monolithic Quantum Dot Discrete Mode Laser on SOI

Single-longitudinal-modelight sources on a silicon platform exhibittremendous potential in data transmission, integrated on-chip opticalinterconnects, and optical ranging. A unique InAs/GaAs quantum dotdiscrete mode (DM) laser directly grown on a silicon-on-insulator(SOI) substrate with embedded silicon gratings has been demonstratedhere, which is regrowth-free and compatible with integrated siliconphotonics. Attributed to refractive index perturbation and opticalfeedback from embedded silicon gratings prepatterned on the SOI substrate,this DM laser can provide stable single-mode operation with a thresholdcurrent of 45 mA and an output power of 9 mW. The maximum opticalsignal-to-noise ratio (OSNR) achieved is 43.6 dB with an optical linewidthof 157 kHz. The 3 dB direct modulation bandwidth is measured as 3.6GHz. The DM laser can be externally modulated at 70 Gbit/s with non-return-to-zero(NRZ) modulation format and 80 Gbit/s under 4-level pulsed amplitude(PAM4) modulation format. Such SOI-based DM laser paves the way towardlarge-scale and high-power on-chip integrated lasers.