Impact of the precursor gas ratio on dispersion engineering of broadband silicon nitride microresonator frequency combs

Published

November 29, 2021

Author(s)

Gregory Moille, Daron Westly, Gregory Simelgor, Kartik Srinivasan

Abstract

Microresonator frequency combs, or microcombs, have gained wide appeal for their rich nonlinear physics and wide range of applications. Stoichiometric silicon nitride films grown via low-pressure chemical vapor deposition (LPCVD), in particular, are widely used in chip-integrated Kerr microcrocombs. Critical to such devices is the ability to control the microresonator dispersion, which has contributions from both material refractive index dispersion and geometric confinement. Here, we show that modifications to the LPCVD growth conditions, specifically the ratio of the gaseous precursors, has a significant impact on material dispersion and hence the overall microresonator dispersion. In contrast to the many efforts focused on comparison between Si-rich films and stoichiometric (Si$_3$N$_4$) films, here we entirely focus on films that are within the nominally stoichiometric growth regime. We further show that microresonator geometric dispersion can be tuned to compensate for changes in the material dispersion.

Citation

Optics Letters

Volume

46

Issue

23

Pub Type

Journals

Download Paper

https://doi.org/10.1364/OL.440907

Local Download

Keywords

microcomb, nano fabrication, silicon nitride

Citation

Moille, G. , Westly, D. , Simelgor, G. and Srinivasan, K. (2021), Impact of the precursor gas ratio on dispersion engineering of broadband silicon nitride microresonator frequency combs, Optics Letters, [online], https://doi.org/10.1364/OL.440907, https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=933032 (Accessed October 8, 2025)