Self-Injection-Locked Heterogeneous InP/SiN Lasers at Wafer Scale

I. Kudelin, B. Song, Kaustubh Asawa, Boqiang Shen, Joel Guo, Yang Shen, A. Dorche, Jonathan Peters, Glenn Kim, Nathan Kim, C. Nguyen, Theodore Morin, John E. Bowers, Zeyu Zhang, Chong Zhang, T. Komljenovic, Minh A. Tran

Ultra-low-noise lasers are essential in high-performance systems, and heterogeneous integration offers the most promising path towards manufacturing them at high volumes with low size, weight, power, and cost. Self-injection locking is a well-established technique for dramatically reducing frequency noise inherent to III-V lasers, yet prior demonstrations have relied on hybrid integration incompatible with high-volume manufacturing and wafer-scale testing. In this work we address this gap by presenting a fully integrated heterogeneous silicon nitride laser and photonic circuit platform near 1560 nm, leveraging a compact, multi-layer silicon nitride architecture to preserve ultra-high quality factors above 40 million. We demonstrate Hertz-level-linewidth self-injection-locked lasers, densely and simultaneously co-integrated with semiconductor optical amplifiers and photodetectors, fabricated with high yield across multiple 100-mm wafers and characterized at wafer level, confirming the suitability of this platform for mass production.