Centi-combs: Low-noise sub-GHz repetition-rate soliton frequency combs from crystalline resonators
Abstract
We demonstrate low-noise Kerr soliton frequency combs with repetition rates below 1~GHz in ultrahigh-Q crystalline magnesium fluoride resonators. Single soliton states with repetition rates of 0.90 GHz, 1.19 GHz, 1.59 GHz, 2.48 GHz, and 4.10 GHz are observed with continuous-wave laser excitation. The near-GHz soliton repetition frequency exhibits a single-sideband phase noise of -137 dBc/Hz at a 100 kHz offset, surpassing state-of-the-art microwave generators. These ``centi-combs'' bridge the gap between conventional mode-locked lasers and microresonator frequency combs, providing a new route towards real-time sampling, optical-to-microwave synchronization, and hybrid optical clock networks in a compact form. This work expands the operational range of Kerr soliton microcombs from the terahertz to the sub-gigahertz domain, opening new frontiers for frequency comb technologies.
Keywords
Cite
@article{arxiv.2510.21132,
title = {Centi-combs: Low-noise sub-GHz repetition-rate soliton frequency combs from crystalline resonators},
author = {Tatsuki Murakami and Keisuke Ogawa and Hajime Kumazaki and Shun Fujii},
journal= {arXiv preprint arXiv:2510.21132},
year = {2026}
}
Comments
4 pages, 3 figures