A compact optical frequency division system with magnesium-fluoride-microresonator-based frequency references and silicon-nitride-microresonator-based comb generators is reported, offering a soliton pulse train at 25-GHz microwaves with an absolute phase noise of –141 dBc Hz–1 and timing noise below 546 zs Hz–1/2 at a 10-kHz offset frequency.
- Xing Jin
- Zhenyu Xie
- Qi-Fan Yang
