Optimizing the deployment of quantum key distribution switch-based networks

TL;DR

This paper proposes a cost-effective QKD network architecture using optical switches to reduce device count and expenses, maintaining high secret key rates over long distances.

Contribution

It introduces a switch-based QKD network design that significantly lowers deployment costs while preserving most of the network's throughput.

Findings

Resource savings of up to 28% achieved.

Throughput reduction limited to 8%.

Effective over a 670 km, 8-node network.

Abstract

Quantum key distribution (QKD) networks provide an infrastructure for establishing information-theoretic secure keys between legitimate parties via quantum and authentic classical channels. The deployment of QKD networks in real-world conditions faces several challenges, which are related in particular to the high costs of QKD devices and the condition to provide reasonable secret key rates. In this work, we present a QKD network architecture that provides a significant reduction in the cost of deploying QKD networks by using optical switches and reducing the number of QKD receiver devices, which use single-photon detectors. We describe the corresponding modification of the QKD network protocol. We also provide estimations for a network link of a total of 670 km length consisting of 8 nodes, and demonstrate that the switch-based architecture allows achieving significant resource savings of up to 28%, while the throughput is reduced by 8% only.