Integration of quantum key distribution and high-throughput classical communications in field-deployed multi-core fibers
Year: 2025
Authors: Wu Q., Ribezzo D., Di Sciullo G., Cocchi S., Shaji DA., Zischler LA., Luis R., Serena P., Lasagni C., Bononi A., Hayashi T., Gagliano A., Martelli P., Gatto A., Parolari P., Boffi P., Bacco D., Zavatta A., Zhu YX., Hu WS., Xu ZP., Shtaif M., Marotta A., Graziosi F., Mecozzi A., Antonelli C.
Autors Affiliation: Univ Aquila, Dept Phys & Chem Sci, I-67100 Laquila, Italy; Hong Kong Polytech Univ, Photon Res Inst, Dept Elect & Elect Engn, Hong Kong, Peoples R China; Shanghai Jiao Tong Univ, Dept Elect Engn, Shanghai 200240, Peoples R China; Univ Firenze, Dept Phys & Astron, I-50019 Florence, Italy; NICT, Photon Syst Lab, Koganei, Tokyo 1840015, Japan; Univ Parma, Dept Engn & Architecture, I-43124 Parma, Italy; CNIT Natl Lab Adv Opt Fibers Photon, I-67100 Laquila, Italy; Sumitomo Elect Ind Ltd, Yokohama, Kanagawa 2448588, Japan; Politecn Milan, Dept Elect Informat & Bioengn, I-20133 Milan, Italy; Natl Inst Opt CNR INO, I-50125 Florence, Italy; Pengcheng Lab, Shenzhen 518055, Peoples R China; Tel Aviv Univ, Dept Phys Elect, IL-69978 Tel Aviv, Israel.
Abstract: Quantum key distribution (QKD) is a secure communication method for sharing symmetric cryptographic keys based on the principles of quantum physics. Its integration into the fiber-optic network infrastructure is important for ensuring privacy in optical communications. Multi-core fibers (MCFs), the likely building blocks of future high-capacity optical networks, offer new opportunities for such integration. Here, we experimentally demonstrate, for the first time, the coexistence of discrete-variable QKD and high-throughput classical communication in the C-band over a field-deployed MCF with industry standard cladding diameter of 125 mu m. Specifically, we demonstrate successful secure-key establishment in one core of a 25.2-km uncoupled-core MCF, while simultaneously loading the remaining three cores with full C-band counter-propagating classical traffic at an aggregate net rate of 110.8 Tb/s. By proposing and experimentally validating an improved analytical model for inter-core spontaneous Raman scattering noise, we find that this configuration is optimal for our deployed MCF link as it is immune to four-wave mixing, that becomes relevant when the quantum and classical signals are propagating in the same direction. Our findings make an important step forward in demonstrating the integration of QKD and classical transmission in uncoupled-core multi-core fibers for next-generation optical communication networks.
Journal/Review: LIGHT-SCIENCE & APPLICATIONS
Volume: 14 (1) Pages from: 274-1 to: 274-16
More Information: This work was funded by the European Commission through European Union-Next Generation EU, under the Italian National Recovery and Resilience Plan, Mission 4, Component 2, Investment 1.3, CUP B53C22003970001, partnership on Telecommunications of the Future (PE00000001-program RESTART), and in the Digital Europe Program under project QUID (Quantum Italy Deployment) Grant Agreement 101091408. D.B. acknowledges funding from the European Commission through ERC StG, QOMUNE, Grant Agreement 101077917.KeyWords: Raman-scattering; Channel; ImpactDOI: 10.1038/s41377-025-01982-z
