Investigation of Q degradation in low-loss Si3N4 from heterogeneous laser integration

TL;DR

This paper demonstrates the preservation and recovery of high Q factors in Si3N4 photonic resonators during heterogeneous laser integration, crucial for scalable high-performance photonic devices.

Contribution

It shows that Si3N4 resonators maintain high Qs over 100 million during laser fabrication, with controllable recovery after processing steps.

Findings

Q degradation occurs during fabrication steps

Annealing recovers Q to over 100 million

High Qs are maintained on a fully integrated platform

Abstract

High-performance, high-volume-manufacturing Si3N4 photonics requires extremely low waveguide losses augmented with heterogeneously integrated lasers for applications beyond traditional markets of high-capacity interconnects. State-of-the-art quality factors (Q) over 200 million at 1550 nm have been shown previously; however, maintaining high Qs throughout laser fabrication has not been shown. Here, Si3N4 resonator intrinsic Qs over 100 million are demonstrated on a fully integrated heterogeneous laser platform. Qi is measured throughout laser processing steps, showing degradation down to 50 million from dry etching, metal evaporation, and ion implant steps, and controllable recovery to over 100 million from annealing at 250C - 350C.