title: A broadband chip-scale optical frequency synthesizer at 2.7 × 10(-16) relative uncertainty.
abstract: Optical frequency combs-coherent light sources that connect optical frequencies with microwave oscillations-have become the enabling tool for precision spectroscopy, optical clockwork, and attosecond physics over the past decades. Current benchmark systems are self-referenced femtosecond mode-locked lasers, but Kerr nonlinear dynamics in high-Q solid-state microresonators has recently demonstrated promising features as alternative platforms. The advance not only fosters studies of chip-scale frequency metrology but also extends the realm of optical frequency combs. We report the full stabilization of chip-scale optical frequency combs. The microcomb's two degrees of freedom, one of the comb lines and the native 18-GHz comb spacing, are simultaneously phase-locked to known optical and microwave references. Active comb spacing stabilization improves long-term stability by six orders of magnitude, reaching a record instrument-limited residual instability of [Formula: see text]. Comparing 46 nitride frequency comb lines with a fiber laser frequency comb, we demonstrate the unprecedented microcomb tooth-to-tooth relative frequency uncertainty down to 50 mHz and 2.7 × 10(-16), heralding novel solid-state applications in precision spectroscopy, coherent communications, and astronomical spectrography.
authors.affiliation: Mesoscopic Optics and Quantum Electronics Laboratory, University of California, Los Angeles, CA 90095, USA.
authors.forename: Shu-Wei
authors.initials: SW
authors.lastname: Huang
authors.affiliation: Mesoscopic Optics and Quantum Electronics Laboratory, University of California, Los Angeles, CA 90095, USA.
authors.forename: Jinghui
authors.identifier: 0000-0001-5615-4082
authors.initials: J
authors.lastname: Yang
authors.affiliation: Institute of Microelectronics, Agency for Science, Technology and Research (ASTAR), Singapore 117865, Singapore.
authors.forename: Mingbin
authors.identifier: 0000-0002-2360-7089
authors.initials: M
authors.lastname: Yu
authors.affiliation: Department of Physics, Columbia University, New York, NY 10027, USA.
authors.forename: Bart H
authors.identifier: 0000-0001-6873-2855
authors.initials: BH
authors.lastname: McGuyer
authors.affiliation: Institute of Microelectronics, Agency for Science, Technology and Research (ASTAR), Singapore 117865, Singapore.
authors.forename: Dim-Lee
authors.initials: DL
authors.lastname: Kwong
authors.affiliation: Department of Physics, Columbia University, New York, NY 10027, USA.
authors.forename: Tanya
authors.initials: T
authors.lastname: Zelevinsky
authors.affiliation: Mesoscopic Optics and Quantum Electronics Laboratory, University of California, Los Angeles, CA 90095, USA.
authors.forename: Chee Wei
authors.initials: CW
authors.lastname: Wong
mesh_terms: D001256:Astronomy / Q000295:instrumentation*; D004867:Equipment Design; D005336:Fiber Optic Technology / Q000295:instrumentation*; D013057:Spectrum Analysis / Q000295:instrumentation*; D013685:Telecommunications / Q000295:instrumentation*
keywords: Optical frequency comb; astronomical spectrography; chip-scale; coherent communications; precision spectroscopy