Fig. 3: Heterogeneous SiN lasers self-injection locking to high-Q SiN ring resonators.
From: High-performance lasers for fully integrated silicon nitride photonics
a Schematic illustration of three potential lasing conditions with a III–V/Si/SiN platform. Each condition relies on different feedback mechanism and results in different laser coherence. b Transmission of a high-Q SiN ring resonator with 5-GHz FSR and the corresponding intrinsic Q factors around the SiN laser resonance. Bottom shows the zoom-in resonance transmission used for self-injection locking with fitted curve (shown in red). c Laser frequency noise of a high-coherence SiN laser at free-running state (blue) and self-injection-locked state (purple) to a high-Q SiN ring resonator. d Optical spectrum showing frequency comb generation of a high-power laser on III-V/Si/SiN platform self-injection locked to a 30-GHz FSR high-Q ring resonator with normal dispersion.
