title: Chip-based frequency combs with sub-100 GHz repetition rates.
abstract: By fabricating high-Q silicon-nitride spiral resonators, we demonstrate frequency combs spanning over 200 nm with free spectral ranges (FSRs) of 80, 40, and 20 GHz using cascaded four-wave mixing. We characterize the RF beat note for the 20 GHz FSR comb, and the measured linewidth of 3.6 MHz is consistent with thermal fluctuations in the resonator due to amplitude noise of the pump source. These combs represent an important advance towards developing a complementary metal-oxide-semiconductor (CMOS)-based system capable of linking the optical and electronic regimes.
authors.affiliation: School of Applied and Engineering Physics, Cornell University, Ithaca, New York 14853, USA. arj46@cornell.edu
authors.forename: Adrea R
authors.initials: AR
authors.lastname: Johnson
authors.forename: Yoshitomo
authors.initials: Y
authors.lastname: Okawachi
authors.forename: Jacob S
authors.initials: JS
authors.lastname: Levy
authors.forename: Jaime
authors.initials: J
authors.lastname: Cardenas
authors.forename: Kasturi
authors.initials: K
authors.lastname: Saha
authors.forename: Michal
authors.initials: M
authors.lastname: Lipson
authors.forename: Alexander L
authors.initials: AL
authors.lastname: Gaeta