Digital Doppler-cancellation servo for ultra-stable optical frequency dissemination over fiber
arXiv:2111.07891 · doi:10.1109/TUFFC.2021.3125066
Abstract
Progress made in optical references, including ultra-stable Fabry-Perot cavities, optical frequency combs and optical atomic clocks, have driven the need for ultra-stable optical fiber networks. Telecom-wavelength ultra-pure optical signal transport has been demonstrated on distances ranging from the laboratory scale to the continental scale. In this manuscript, we present a Doppler-cancellation setup based on a digital phase-locked loop for ultra-stable optical signal dissemination over fiber. The optical phase stabilization setup is based on a usual heterodyne Michelson-interferometer setup, while the Software Defined Radio (SDR) implementation of the phase-locked loop is based on a compact commercial board embedding a field programmable gate array, analog-to-digital and digital-to-analog converters. Using three different configurations including an undersampling method, we demonstrate a 20 m long fiber link with residual fractional frequency instability as low as at 1000 s, and an optical phase noise of dBc/Hz at 1 Hz with a telecom frequency carrier.
11 pages, 6 figures
References in corpus (9)
- An Al quantum-logic clock with systematic uncertainty below
- Coherent optical frequency transfer at 5e-19 over a doubled 642 km fiber link
- An ultrastable silicon cavity in a continuously operating closed-cycle cryostat at 4 K
- Two-Way Optical Frequency Comparisons Over 100km Telecommunication Network Fibers
- Tackling the Limits of Optical Fiber Links
- Microcontroller-based locking in optics experiments
- Digital laser frequency and intensity stabilization based on the STEMlab platform (originally Red Pitaya)
- Ultra-compact reference ULE cavity
- Beyond the fundamental noise limit in coherent optical fiber links