Practical high-dimensional quantum key distribution protocol over deployed multicore fiber

Year: 2024

Authors: Zahidy M., Ribezzo D., De Lazzari C., Vagniluca I., Biagi N., Muller R., Occhipinti T., Oxenlowe LK., Galili M., Hayashi T., Cassioli D., Mecozzi A., Antonelli C., Zavatta A., Bacco D.

Autors Affiliation: Tech Univ Denmark, Dept Elect & Photon Engn, Orsteds Pl, DK-2800 Lyngby, Denmark; Univ Aquila, Dept Phys & Chem Sci, Laquila, Italy; CNR, Ist Nazl Ott, I-50125 Florence, Italy; Univ Napoli Federico II, Naples, Italy; QTI Srl, I-50125 Florence, Italy; Sumitomo Elect Ind Ltd, Opt Commun Lab, Yokohama 2448588, Japan; Univ Aquila, Dept Informat Engn Comp Sci & Math, Laquila, Italy; CNIT, Natl Lab Adv Opt Fibers Photon FIBERS, Laquila, Italy; Univ Florence, Dept Phys & Astron, Via Sansone 1, I-50019 Florence, Italy.

Abstract: Quantum key distribution (QKD) is a secure communication scheme for sharing symmetric cryptographic keys based on the laws of quantum physics, and is considered a key player in the realm of cyber-security. A critical challenge for QKD systems comes from the fact that the ever-increasing rates at which digital data are transmitted require more and more performing sources of quantum keys, primarily in terms of secret key generation rate. High-dimensional QKD based on path encoding has been proposed as a candidate approach to address this challenge. However, while proof-of-principle demonstrations based on lab experiments have been reported in the literature, demonstrations in realistic environments are still missing. Here we report the generation of secret keys in a 4-dimensional hybrid time-path-encoded QKD system over a 52-km deployed multicore fiber link forming by looping back two cores of a 26-km 4-core optical fiber. Our results indicate that robust high-dimensional QKD can be implemented in a realistic environment by combining standard telecom equipment with emerging multicore fiber technology. High-dimensional QKD would in principle allow for several advantages over its bidimensional counterpart, but in-the-field demonstrations are missing. Here, the authors realise 4- dimensional hybrid time-path-encoded QKD using a 52-km deployed multicore fiber link.

Journal/Review: NATURE COMMUNICATIONS

Volume: 15 (1)      Pages from: 1651-1  to: 1651-6

More Information: C.A. and A.M. are funded by QUID (Quantum Italy Deployment) funded by the European Commission in the Digital Europe Programme under the grant agreement No 101091408., L.O. received funding from the Center of Excellence SPOC (ref DNRF123), A.Z. received funding from the Project QuONTENT under the Progetti di Ricerca, CNR program funded by the Consiglio Nazionale delle Ricerche (CNR) and by the European Union-PON Ricerca e Innovazione 2014-2020 FESR-Project ARS01/00734 QUANCOM. D.B received funding from the IFD DK project Fire-Q (No. 9090-00031B), by EQUO (European Quantum Ecosystem) funded by the European Commission in the Digital Europe Programme under the grant agreement No 101091561 and by the European Union ERC project QOMUNE (101077917). The authors acknowledge OpenStreetMap40 for providing the map of L’Aquila City, Italy.
KeyWords: communication technology; computer security; encryption; Italy; multicore fiber technology; photon; quantum key distribution; quantum theory; telecommunication; fiber
DOI: 10.1038/s41467-024-45876-x

Citations: 3
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