Frequency comb-based microwave transfer over fiber with $7\times 10^{-19}$ instability using fiber-loop optical-microwave phase detectors

Abstract

We demonstrate a remote microwave/radio-frequency (RF) transfer technique based on the stabilization of a fiber link using a fiber-loop optical-microwave phase detector (FLOM-PD). This method compensates for the excess phase fluctuations introduced in fiber transfer by direct phase comparison between the optical pulse train reflected from the remote site and the local microwave/RF signal using the FLOM-PD. This enables sub-fs resolution and long-term stable link stabilization while having wide timing detection range and less demand in fiber dispersion compensation. The demonstrated relative frequency instability between 2.856-GHz RF oscillators separated by a 2.3-km fiber link is $7.6\times 10^{-18}$ and $6.5\times 10^{-19}$ at 1000 s and 82500 s averaging time, respectively.

5 pages, 4 figures

References in corpus (2)

• Sub-femtosecond synchronization of microwave oscillators with mode-locked Er-fiber lasers
• Suppression of amplitude-to-phase noise conversion in balanced optical-microwave phase detectors

Cited by in corpus (6)

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• Time-Frequency Transfer over Optical Fiber
• Open-Loop Polarization Mode Dispersion Mitigation for Fibre-Optic Time and Frequency Transfer
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• Evaluation at the Remote Site for Ultra-stable Radio Frequency Dissemination via Fiber Links
• Ultrasensitive, high-dynamic-range and broadband strain sensing by time-of-flight detection with femtosecond-laser frequency combs