Provably secure and practical quantum key distribution over 307 km of optical fibre

By B. Korzh, Charles Ci Wen Lim, Raphael Houlmann, Nicolas Gisin, M. Li, D. Nolan, B. Sanguinetti, R. Thew, H. Zbinden. Nature Photonics, 2014

523 citations recorded by the source corpus.

A discrete-variable quantum key distribution system that is capable of distributing a provably-secure cryptographic key over 307 kilometres is demonstrated at a telecom wavelength. Proposed in 1984, quantum key distribution (QKD) allows two users to exchange provably secure keys via a potentially insecure quantum channel1. Since then, QKD has attracted much attention and significant progress has been made both in theory and practice2,3. On the application front, however, the operating distance of practical fibre-based QKD systems is limited to about 150 km (ref. 4), mainly due to the high background noise of practical single-photon detectors5,6 and inefficient finite-key security analysis7,8,9. Here, we present, for the first time, a compact and autonomous QKD system that is capable of distributing provably secure cryptographic keys over 307 km of optical fibre. This is achieved by using semiconductor single-photon detectors with record low background noise10 and a novel finite-key security analysis, which is efficient even for short key lengths. This demonstrates the feasibility of practical long-distance QKD based on standard fibre-optic telecom components.

Subfields: Artificial Intelligence, Atomic and Molecular Physics, and Optics

View Paper: https://www.semanticscholar.org/paper/bec8ffb168b08dc8ba2e64b9f31ed4d8a8848882

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Citations in the corpus

Chip-based quantum key distribution (2015, methodology): “2 dB/km was assumed (standard within telecommunications fibres at 1550 nm), although rates could be improved through use of low loss fibres [24], and optimising the SNSPDs for ultra low dark counts [25].”
Colloquium: Strongly interacting photons in one-dimensional continuum (2016, background): “…with microwave photons show great promise for implementing quantum nodes, the implementation of long-distance 15 quantum channels using optical photons is very far advanced, with records distances of > 100 for free-space and in-fiber transmissions (Korzh et al., 2015; Ursin et al., 2007).”
Distributing Secret Keys with Quantum Continuous Variables: Principle, Security and Implementations (2015, background): “The quest for high-performance quantum key distribution systems in the last few years has led to several successful demonstrations based on these discrete-variable or distributed-phase reference protocols [8–11].”
Practical challenges in quantum key distribution (2016, unknown): “InGaAs avalanche photodiodes can tolerate losses of 30 and 52 dB when cooled to − 30 and − 120 °C, 41,61 respectively, whereas SNSPDs cooled to cryogenic temperatures have been demonstrated to withstand a record loss of 72 dB. 62 This loss is equivalent to 360 km of standard single mode ﬁ bre or…”
Orbital Angular Momentum States Enabling Fiber-based High-dimensional Quantum Communication (2018, background): “[7] B.”