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

TitleImpact of the precursor gas ratio on dispersion engineering of broadband silicon nitride microresonator frequency combs
Publication TypeJournal Article
Year of Publication2021
AuthorsG. Moille, D. Westly, G. Simelgor, and K. Srinivasan
JournalOpt. Lett.
Volume46
Pagination5970-5973
Date PublishedDEC 1
Type of ArticleArticle
ISSN0146-9592
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 microcombs. 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 ratio of the gaseous precursors in LPCVD growth have a significant impact on material dispersion and hence the overall microresonator dispersion. In contrast to the many efforts focused on comparisons between Si-rich films and stoichiometric (Si3N4) films, here, we focus on films whose precursor gas ratios should nominally place them in the stoichiometric regime. We further show that microresonator geometric dispersion can be tuned to compensate for changes in the material dispersion. (C) 2021 Optical Society of America.

DOI10.1364/OL.440907