40-user fully connected entanglement-based quantum key distribution network without trusted node

Xu Liu,Lixing You,Kaiyu Cui,Rong Xue,Hao Li,Xue Feng,Yidong Huang,Jingyuan Liu,Wei Zhang,Zhen Wang,Heqing Wang,Fang Liu

doi:10.1186/s43074-022-00048-2

Abstract

Quantum key distribution (QKD) would play an important role in future information technologies due to its theoretically proven security based on the laws of quantum mechanics. How to realize QKDs among multiple users in an effective and simple way is crucial for its real applications in communication networks. In this work, we propose and demonstrate a fully connected QKD network without trusted node for a large number of users. Using flexible wavelength division multiplexing/demultiplexing and space division multiplexing, entanglement resources generated by a broadband energy-time entangled quantum light source are distributed to 40 users. Any two users share a part of entanglement resources, by which QKD is established between them. As a result, it realizes a fully connected network with 40 users and 780 QKD links. The performance of this network architecture is also discussed theoretically, showing its potential on developing quantum communication networks with large user numbers owing to its simplicity, scalability, and high efficiency.

Highlights

Quantum key distribution (QKD) has been regarded as a mature technique in security applications of quantum communication [1, 2]
The remaining 10 entanglement resources are used to connect users between the subnets. These wavelength channels are multiplexed by commercial dense wavelength division multiplexing components, as illustrated in Fig. 1(c), and sent to the passive beam splitters
Since two specific users receive photons from the provider through transmission fibers of 1 and 2 km respectively, the Discussion In this work, we proposed a QKD network architecture with two layers, based on quantum entanglement distribution by both wavelength division multiplexing (WDM) and space division multiplexing (SDM)

Summary

Introduction

Quantum key distribution (QKD) has been regarded as a mature technique in security applications of quantum communication [1, 2]. Since the first QKD protocol BB84 [3] was proposed, QKD has been actively developed both in security proofing [4, 5] and in practical implementation [6, 7]. In the last few years, twin-field QKD (TF-QKD) [15,16,17,18] has been investigated, which is based on single-photon interference and can provide high key rates over long distances to surpass the rate-distance limit of repeaterless QKD. Based on TF-QKD, the secure distance of QKD in field test was extended to 511 km through sending-or-not-sending (SNS) protocol [19]

Methods

Results

Discussion

Conclusion