Frequency-bin entanglement-based Quantum Key Distribution
Anno: 2025
Autori: Tagliavacche N., Borghi M., Guarda G., Ribezzo D., Liscidini M., Bacco D., Galli M., Bajoni D.
Affiliazione autori: Univ Pavia, Dipartimento Fis, Via Bassi 6, Pavia, Italy; European Lab Nonlinear Spect LENS, Sesto Fiorentino, Italy; CNR Natl Inst Opt CNR INO, Florence, Italy; Univ Laquila, Dept Phys & Chem Sci, Laquila, Italy; QTI S r l, Florence, Italy; Univ Florence, Dept Phys & Astron, Sesto Fiorentino, Italy; Univ Pavia, Dipartimento Ingn Industriale & Informaz, Via Ferrata 5, Pavia, Italy.
Abstract: Entanglement is an essential ingredient in many quantum communication protocols. In particular, entanglement can be exploited in quantum key distribution (QKD) to generate two correlated random bit strings whose randomness is guaranteed by the nonlocal property of quantum mechanics. Most of QKD protocols tested to date rely on polarization and/or time-bin encoding. Despite compatibility with existing fiber-optic infrastructure and ease of manipulation with standard components, frequency-bin QKD have not yet been fully explored. Here we report a demonstration of entanglement-based QKD using frequency-bin encoding. We implement the BBM92 protocol using photon pairs generated by two independent, high-finesse, ring resonators on a silicon photonic chip. We perform a passive basis selection scheme and simultaneously record sixteen projective measurements. A key finding is that frequency-bin encoding is sensitive to the random phase noise induced by thermal fluctuations of the environment. To correct for this effect, we developed a real-time adaptive phase rotation of the measurement basis, achieving stable transmission over a 26 km fiber spool with a secure key rate >= 4.5 bit/s. Our work introduces a new degree of freedom for the realization of entangled based QKD protocols in telecom networks.
Giornale/Rivista: NPJ QUANTUM INFORMATION
Volume: 11 (1) Da Pagina: 60-1 A: 60-8
Maggiori informazioni: The authors acknowledge Federico Andrea Sabattoli, Houssein El Dirani, Laurene Youssef, Camille Petit-Etienne, Erwine Pargon, and Corrado Sciancalepore for the design and fabrication of the sample. The device has been fabricated at CEA-LETI (Grenoble) on a 200 mm silicon-on-insulator wafer manufactured by SOITEC (Bernin), and is part of a previous collaboration. D.B. acknowledges the support of Italian MUR and the European Union – Next Generation EU through the PRIN project number F53D23000550006 – SIGNED. M.B., M.G and M.L. acknowledge the PNRR MUR project PE0000023-NQSTI. N.T acknowledges the HyperSpace project (project ID 101070168). D. Bacco acknowledges the support of the European Union (ERC, QOMUNE, 101077917, the Project SERICS (PE00000014) under the MUR National Recovery and Resilience Plan funded by the European Union – NextGenerationEU. D.R. acknowledges the Project QUID (Quantum Italy Deployment) funded by the European Commission in the Digital Europe Programme under the grant agreement No 101091408.DOI: 10.1038/s41534-025-00991-5
