近日，瑞士应用物理研究机构的Hugo Zbinden小组研究了利用快速单光子探测器和实时密钥提纯，开发高密钥速率量子密钥分发系统的可能性。相关结果已于2023年3月9日在国际学术期刊《自然—光子学》上发表。

该研究小组提出了一种定制的多像素超导纳米线单光子探测器，旨在保证高计数率和精确的时间区分。借助于探测器的性能，并将其与快速采集和实时密钥提纯电子器件相结合，研究人员消除了接收端的两个主要障碍，并相对于目前的技术水平实现了密钥速率的显著提高。结合一个简单的2.5 GHz时钟time-bin量子密钥分发系统，通过实时密钥提纯，他们成功地实现了在10 km的距离上以64 Mbps的速率生成密钥，在102.4 km的距离上以3 Mbps的速率生成密钥。

据了解，量子密钥分发已经成为在大规模量子计算机存在的情况下保障信息安全的最可行方案，得益于过去20年所取得的持续进展，现在已经商用化。然而，由于接收端存在多个瓶颈，密钥生成速率仅限于略高于10 Mbps。

附：英文原文

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

Author: Grnenfelder, Fadri, Boaron, Alberto, Resta, Giovanni V., Perrenoud, Matthieu, Rusca, Davide, Barreiro, Claudio, Houlmann, Raphal, Sax, Rebecka, Stasi, Lorenzo, El-Khoury, Sylvain, Hnggi, Esther, Bosshard, Nico, Bussires, Flix, Zbinden, Hugo

Issue&Volume: 2023-03-09

Abstract: 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 10Mbps 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 64Mbps over a distance of 10.0km and at a rate of 3.0Mbps over a distance of 102.4km with real-time key distillation.

DOI: 10.1038/s41566-023-01168-2

Source: https://www.nature.com/articles/s41566-023-01168-2