• Advanced Photonics
  • Vol. 3, Issue 5, 055002 (2021)
Xiaodong Zheng1、†, Peiyu Zhang1, Renyou Ge2, Liangliang Lu1, Guanglong He1, Qi Chen1, Fangchao Qu1, Labao Zhang1、*, Xinlun Cai2、*, Yanqing Lu1, Shining Zhu1, Peiheng Wu1, and Xiao-Song Ma1、*
Author Affiliations
  • 1Nanjing University, National Laboratory of Solid-state Microstructures, School of Physics, Research Institute of Superconducting Electronics, School of Electronic Science and Engineering, College of Engineering and Applied Sciences, Collaborative Innovation Center of Advanced Microstructures, Nanjing, China
  • 2Sun Yat-sen University, State Key Laboratory of Optoelectronic Materials and Technologies, School of Electronics and Information Technology, Guangzhou, China
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    Integrated photonics provides a route to both miniaturization of quantum key distribution (QKD) devices and enhancing their performance. A key element for achieving discrete-variable QKD is a single-photon detector. It is highly desirable to integrate detectors onto a photonic chip to enable the realization of practical and scalable quantum networks. We realize a heterogeneously integrated, superconducting silicon-photonic chip. Harnessing the unique high-speed feature of our optical waveguide-integrated superconducting detector, we perform the first optimal Bell-state measurement (BSM) of time-bin encoded qubits generated from two independent lasers. The optimal BSM enables an increased key rate of measurement-device-independent QKD (MDI-QKD), which is immune to all attacks against the detection system and hence provides the basis for a QKD network with untrusted relays. Together with the time-multiplexed technique, we have enhanced the sifted key rate by almost one order of magnitude. With a 125-MHz clock rate, we obtain a secure key rate of 6.166 kbps over 24.0 dB loss, which is comparable to the state-of-the-art MDI-QKD experimental results with a GHz clock rate. Combined with integrated QKD transmitters, a scalable, chip-based, and cost-effective QKD network should become realizable in the near future.

    Video Introduction to the Article

    1 Introduction

    Quantum key distribution (QKD) employs the laws of quantum physics to provide information-theoretical security for key exchange.15 Despite the substantial progress in the past 35 years, practical implementations of QKD still deviate from ideal descriptions in security proofs, mainly due to potential side-channel attacks. For instance, a series of loopholes have been identified due to the imperfections of measurement devices.69 Inspired by the time-reversed entanglement-based QKD, measurement-device-independent QKD (MDI-QKD), which removes all detector side attacks, has been proposed.10,11 Instead of relying on the trusted nodes of traditional QKD protocols, MDI-QKD requires only a central node (Charlie) to perform a Bell-state measurement (BSM). The correlations between the two senders (Alice and Bob) can be obtained from the BSM results. Importantly, even if Charlie is not trusted, one can still guarantee the security of the MDI-QKD as long as Charlie can project his two photons onto Bell states. The outstanding features of MDI-QKD invite global experimental efforts, which are mainly based on bulk/fiber components.1220 Despite the additional BSM by Charlie, the key rate17 and the communication distance18 of MDI-QKD can be comparable with those of traditional QKD. Furthermore, the star-like topology of the MDI-QKD quantum network is naturally suited for the metropolitan network with multiple users.2123 Recently, the generalization of the MDI protocol to multipartite schemes has been investigated.2426 It has been shown that the performance of the multipartite schemes can be advantageous to iterative use of independent bipartite protocols.26

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    Xiaodong Zheng, Peiyu Zhang, Renyou Ge, Liangliang Lu, Guanglong He, Qi Chen, Fangchao Qu, Labao Zhang, Xinlun Cai, Yanqing Lu, Shining Zhu, Peiheng Wu, Xiao-Song Ma. Heterogeneously integrated, superconducting silicon-photonic platform for measurement-device-independent quantum key distribution[J]. Advanced Photonics, 2021, 3(5): 055002
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    Category: Letters
    Received: Jun. 17, 2021
    Accepted: Sep. 29, 2021
    Published Online: Nov. 1, 2021
    The Author Email: Zhang Labao (lzhang@nju.edu.cn), Cai Xinlun (caixlun5@mail.sysu.edu.cn), Ma Xiao-Song (xiaosong.ma@nju.edu.cn)