Proof-of-principle demonstration of decoy-state quantum key distribution with biased basis choices
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Proof-of-principle demonstration of decoy-state quantum key distribution with biased basis choices Wen-Zhe Wu1,2,3 · Jian-Rong Zhu1,2,3 · Liang Ji1,2,3 · Chun-Mei Zhang1,2,3 · Qin Wang1,2,3 Received: 18 November 2019 / Accepted: 29 August 2020 © Springer Science+Business Media, LLC, part of Springer Nature 2020
Abstract Decoy-state method has been widely employed in the quantum key distribution (QKD), since it can not only solve photon-number-splitting attacks but also substantially improve the QKD performance. In conventional three-intensity decoy-state proposal, one not only needs to randomly modulate light sources to different intensities, but also has to prepare them into different bases, which may cost a lot of random numbers in practical applications. Here, we propose a simple decoy-state scheme with biased basis choices where the decoy pulses are only prepared in X basis. Through this way, it can save cost of random numbers and further simplify the electronic control system. Moreover, we carry out corresponding proof-of-principle demonstration. By incorporating with lower-loss asymmetric Mach–Zehnder interferometers and superconducting single-photon detectors, we can obtain a secret key rate of 1.65 kbps at 201 km and 19.5 bps at 280 km coiled optical fibers, respectively, showing very promising applications in future quantum communications. Keywords Quantum key distribution · Biased basis choices · Decoy-state method
1 Introduction Quantum key distribution (QKD), as a means of symmetric encryption technique, allows to share secret keys between two legitimate communicating parties (Alice and
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Qin Wang [email protected]
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Institute of Quantum Information and Technology, Nanjing University of Posts and Telecommunications, Nanjing 210003, China
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Broadband Wireless Communication and Sensor Network Technology, Key Lab of Ministry of Education, NUPT, Nanjing 210003, China
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Telecommunication and Networks, National Engineering Research Center, NUPT, Nanjing 210003, China 0123456789().: V,-vol
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Bob) at certain distance even under existence of an eavesdropper, Eve. Its unconditional security based on the laws of quantum physics [1–3] has received widespread attention. Since the first BB84 protocol was proposed by Bennett and Brassard [4], it has been widely implemented with various schemes [5–9]. Nowadays, more and more field test QKD networks have been built in the world [10–15]. Generally, a weak coherent source (WCS) is widely applied in most QKD systems, since the ideal single-photon source is not yet available under current technology. However, this source opens a back door for sophisticated eavesdroppers such as adopting the photon-number-splitting (PNS) attacks [16,17], which significantly degrades the performance of QKD system due to the non-negligible multiphoton components. Fortunately, the decoy-state method [18,19] was proposed as an efficient countermeasure to solve this security issue. Up to date, a great many QKD implementations with decoy-state met
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