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arXiv:2510.16230 · Optica Quantum

Phase-stable optical fiber links for quantum network protocols

Nicholas V. Nardelli, Dileep V. Reddy, Michael B. Grayson, Daniel Sörensen, Martin J. Stevens, Michael D. Mazurek, Lynden K. Shalm, Tara M. Fortier

Published Feb 6, 2026• 4 citations
arXivHTMLPDF

Abstract

We demonstrate the distribution of single-photon-level pulses from a mode-locked laser source over a phase-stable fiber link, achieving an optical timing jitter of less than 100 as over 10 minutes of data accumulation. This stability enables a fidelity greater than 0.998 between two stabilized 2.1 km long deployed fiber links. Building on time and frequency metrology techniques traditionally used for high-stability optical atomic clock signal distribution, we use time and frequency multiplexing to achieve an isolation of quantum and classical channels of 8×10 10 . Our results mark a necessary step towards scalable, high-rate quantum networks with a provable quantum advantage.

DOI
10.1364/opticaq.582298

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We demonstrate the distribution of single-photon-level pulses from a mode-locked laser source over a phase-stable fiber link, achieving an optical timing jitter of less than 100 as over 10 minutes of data accumulation. This stability enables a fidelity greater than 0.998 between two stabilized 2.1 km long deployed fiber links. Building on time and frequency metrology techniques traditionally used for high-stability optical atomic clock signal distribution, we use time and frequency multiplexing to achieve an isolation of quantum and classical channels of 8×10 10 . Our results mark a necessary step towards scalable, high-rate quantum networks with a provable quantum advantage.
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Phase coherent fibers (PCF) are essential to distribute nearly monochromatic photons, ultra-stable in their frequency and phases, which have demanding requirements for state-of-the-art networked experiments, quantum as well as very high-speed communications. We report the development of a system that produces PCF links, also actively corrects the unavoidable slow frequency drift of the source laser. The PCF follows white phase noise limited σo × τ−1 stability behavior having σo values 1.9(2) × 10−16 and 2.6(1) × 10−16 for a 3.3 km field-deployed and 71 km spool fibers, respectively, with up to 47.5 dB suppression of the phase noise compared to a normal fiber. Additionally, the system is featured to correct the source laser’s 33.8 mHz/s frequency drift to as low as ≃ 0.05 mHz/s. Therefore, this all-in-one solution producing a quantum link can potentially enhance the effectiveness of the twin field quantum key distribution (TF-QKD) by nearly a 73-fold reduction of the QBER that arises from using unstabilized fiber links, as well as relaxes the laser frequency drift correction constraints by severalfold. The authors develop a technique to generate Phase Coherent optical Fibers (PCF) with additional capability of active correction of the source laser’s frequency drift. PCF is capable in distributing nearly monochromatic and low phase noise photons, which has demanding requirements in quantum communication, distributed sensing, time & frequency metrology.