Chip-based frequency combs with sub-100 GHz repetition rates

Adrea R Johnson; Yoshitomo Okawachi; Jacob S Levy; Jaime Cardenas; Kasturi Saha; Michal Lipson; Alexander L Gaeta

doi:10.1364/OL.37.000875

Chip-based frequency combs with sub-100 GHz repetition rates

Opt Lett. 2012 Mar 1;37(5):875-7. doi: 10.1364/OL.37.000875.

Authors

Adrea R Johnson¹, Yoshitomo Okawachi, Jacob S Levy, Jaime Cardenas, Kasturi Saha, Michal Lipson, Alexander L Gaeta

Affiliation

¹ School of Applied and Engineering Physics, Cornell University, Ithaca, New York 14853, USA. arj46@cornell.edu

PMID: 22378423
DOI: 10.1364/OL.37.000875

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.