Abstract:

Chip-based photonic microresonators are attractive for a multitude of applications owing to their small form factors and compatibility with photonic integration and standard CMOS fabrication. Within the last decade, the ring resonator geometry has gained widespread adoption in the application of optical frequency comb generation. However, these devices often require waveguides several hundreds of nanometers thick, posing a challenge for subtractive fabrication processes where the desired pattern must be chemically etched with the use of a protective “mask” pattern. Here, we demonstrate two procedures for subtractive processing of thick SiN waveguides based on both a polymer-based “soft” photoresist mask and a chromium metallic “hard” mask as etch templates. Optical characterization of our devices fabricated with both soft mask and hard mask techniques demonstrate quality factors of 320k ± 100k and 470k ± 290k., respectively.

Authors: Gabriel Colacion, Lala Rukh, Tara Drake, and Brandon Stone