1. Dispersive-wave induced noise limits in miniature soliton microwave sources
- Author
-
Zhiquan Yuan, Kerry J. Vahala, Lue Wu, Boqiang Shen, Heming Wang, Qi-Fan Yang, Chengying Bao, and Qing-Xin Ji
- Subjects
Nonlinear optics ,Noise reduction ,Science ,General Physics and Astronomy ,Thermal fluctuations ,Physics::Optics ,Micro-optics ,01 natural sciences ,Solitons ,General Biochemistry, Genetics and Molecular Biology ,Article ,010309 optics ,Optics ,0103 physical sciences ,Phase noise ,010306 general physics ,Nonlinear Sciences::Pattern Formation and Solitons ,Jitter ,Physics ,Multidisciplinary ,business.industry ,General Chemistry ,Pulse (physics) ,Nonlinear Sciences::Exactly Solvable and Integrable Systems ,Soliton ,business ,Noise (radio) ,Microwave - Abstract
Compact, low-noise microwave sources are required throughout a wide range of application areas including frequency metrology, wireless-communications and airborne radar systems. And the photonic generation of microwaves using soliton microcombs offers a path towards integrated, low noise microwave signal sources. In these devices, a so called quiet-point of operation has been shown to reduce microwave frequency noise. Such operation decouples pump frequency noise from the soliton’s motion by balancing the Raman self-frequency shift with dispersive-wave recoil. Here, we explore the limit of this noise suppression approach and reveal a fundamental noise mechanism associated with fluctuations of the dispersive wave frequency. At the same time, pump noise reduction by as much as 36 dB is demonstrated. This fundamental noise mechanism is expected to impact microwave noise (and pulse timing jitter) whenever solitons radiate into dispersive waves belonging to different spatial mode families., Here the authors explore the noise spectrum of soliton microcomb when the pump is decoupled from the solitons motion by balancing the Raman shift with the emitted dispersive wave. Based on the analysis of the phase noise and the soliton repetition rate, they identify the uncorrelated thermal fluctuations as underlying mechanism.
- Published
- 2021