Fast single-photon detectors and real-time key distillation enable high secret-key-rate quantum key distribution systems

Quantum key distribution has emerged as the most viable scheme to guarantee information security in the presence of large-scale quantum computers and, thanks to the continuous progress made in the past 20 years, it is now commercially available. However, the secret key rates remain limited to just o...

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Bibliographic Details
Published in:Nature photonics 2023, Vol.17 (5), p.422-426
Main Authors: Grünenfelder, Fadri, Boaron, Alberto, Resta, Giovanni V., Perrenoud, Matthieu, Rusca, Davide, Barreiro, Claudio, Houlmann, Raphaël, Sax, Rebecka, Stasi, Lorenzo, El-Khoury, Sylvain, Hänggi, Esther, Bosshard, Nico, Bussières, Félix, Zbinden, Hugo
Format: Article
Language:English
Subjects:
639/624/400/482
639/766/483/481
Applied and Technical Physics
Computers
Design
Distillation
Efficiency
Nanotechnology
Nanowires
Photonics
Photons
Physics
Physics and Astronomy
Quantum computers
Quantum computing
Quantum cryptography
Quantum Physics
Real time
Sensors
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Summary:Quantum key distribution has emerged as the most viable scheme to guarantee information security in the presence of large-scale quantum computers and, thanks to the continuous progress made in the past 20 years, it is now commercially available. However, the secret key rates remain limited to just over 10 Mbps due to several bottlenecks on the receiver side. Here we present a custom multipixel superconducting nanowire single-photon detector that is designed to guarantee high count rates and precise timing discrimination. Leveraging the performance of the detector and coupling it to fast acquisition and real-time key distillation electronics, we remove two major roadblocks and achieve a considerable increase of the secret key rates with respect to the state of the art. In combination with a simple 2.5-GHz clocked time-bin quantum key distribution system, we can generate secret keys at a rate of 64 Mbps over a distance of 10.0 km and at a rate of 3.0 Mbps over a distance of 102.4 km with real-time key distillation. In combination with a 2.5-GHz clocked time-bin quantum key distribution system, secret keys are generated at a rate of 64 Mbps over a distance of 10.0 km and at a rate of 3.0 Mbps over a distance of 102.4 km with real-time key distillation.
ISSN:1749-4885
1749-4893
DOI:10.1038/s41566-023-01168-2