Stabilization of heterogeneous silicon lasers using Pound-Drever-Hall locking to Si3N4 ring resonators

Abstract: Recent results on heterogeneous Si/III-V lasers and ultra-high Q Si3N4 resonators are implemented in a Pound-Drever-Hall frequency stabilization system to yield narrow linewidth characteristics for a stable on-chip laser reference. The high frequency filtering is performed with Si resonant mirrors in the laser cavity. To suppress close in noise and frequency walk off, the laser is locked to an ultra-high Q Si3N4 resonator with a 30 million quality factor. The laser shows high frequency noise levels of 60 × 10^3 Hz^2/Hz corresponding to 160 kHz linewidth, and the low frequency noise is suppressed 33 dB to 10^3 Hz^2/Hz with the PDH system.

https://doi.org/10.1364/OE.24.013511