Field trial of a three-state quantum key distribution scheme in the Florence metropolitan area

• Published in: EPJ quantum technology Vol. 6; no. 1; pp. 1 - 8
• Main Authors: Bacco, Davide, Vagniluca, Ilaria, Da Lio, Beatrice, Biagi, Nicola, Della Frera, Adriano, Calonico, Davide, Toninelli, Costanza, Cataliotti, Francesco S., Bellini, Marco, Oxenløwe, Leif K., Zavatta, Alessandro
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.12.2019; Springer Nature B.V
• Subjects: Metropolitan areas; Nanotechnology and Microengineering; New technology; Optical communication; Physics; Physics and Astronomy; Quantum cryptography; Quantum Information Technology; Quantum Physics; Spintronics; Synchronism
• ISSN: 2662-4400; 2196-0763
• DOI: 10.1140/epjqt/s40507-019-0075-x

In-field demonstrations in real-world scenarios boost the development of a rising technology towards its integration in existing infrastructures. Although quantum key distribution (QKD) devices are already adopted outside the laboratories, current field implementations still suffer from high costs and low performances, preventing this emerging technology from a large-scale deployment in telecommunication networks. Here we present a simple, practical and efficient QKD scheme with finite-key analysis, performed over a 21 dB-losses fiber link installed in the metropolitan area of Florence (Italy). Coexistence of quantum and weak classical communication is also demonstrated by transmitting an optical synchronization signal through the same fiber link.