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Updated: Apr 17, 2026
07:42
Rapid Repetition Rate Fluctuation Measurement of Soliton Crystals in a Microresonator
Published on: December 15, 2021
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Centi-combs: low-noise sub-GHz repetition-rate soliton frequency combs from crystalline resonators
Optics Letters
|April 15, 2026
Summary
Researchers created low-noise Kerr soliton frequency combs below 1 GHz using ultrahigh-Q resonators. These "centi-combs" achieve phase noise surpassing microwave generators, enabling new applications in optical clock networks and synchronization.
Area of Science:
- Optics and Photonics
- Quantum Optics
- Materials Science
Background:
- Kerr soliton microcombs are crucial for optical frequency generation.
- Achieving low repetition rates (sub-GHz) in microcombs is challenging.
- Ultrahigh-Q resonators are key to enhancing microcomb performance.
Purpose of the Study:
- To demonstrate low-noise Kerr soliton frequency combs with repetition rates below 1 GHz.
- To explore the potential of crystalline magnesium fluoride resonators for microcomb generation.
- To establish new benchmarks for microresonator frequency combs.
Main Methods:
- Utilized ultrahigh-Q crystalline magnesium fluoride micro-resonators.
- Employed continuous-wave laser excitation to generate soliton states.
- Characterized soliton repetition frequencies and phase noise performance.
Main Results:
- Observed single soliton states with repetition rates of 0.90, 1.19, 1.59, 2.48, and 4.10 GHz.
- Achieved a single-sideband phase noise of -137 dBc/Hz at 100 kHz offset for near-GHz repetition frequencies.
- Demonstrated phase noise superior to state-of-the-art microwave generators.
Conclusions:
- The developed "centi-combs" set a new benchmark for microresonator frequency combs.
- This work expands Kerr soliton microcomb operation into the sub-gigahertz domain.
- The technology offers a novel pathway for real-time sampling, optical-to-microwave synchronization, and hybrid optical clock networks.
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