High-Rate 16-node quantum access network based on passive optical network

TL;DR

This paper demonstrates a high-rate 16-node quantum access network using a passive optical network with a novel protocol, achieving significantly higher secret key rates and paving the way for scalable quantum secure networks.

Contribution

It introduces a high-efficiency coherent-state PTMP protocol with real-time calibration and advanced processing, enabling multiple users to generate secret keys simultaneously at high rates.

Findings

Average secret key rate of 2.086 Mbps per user

Achieved two orders of magnitude higher key rate than previous work

Demonstrated practical, scalable quantum access network

Abstract

Quantum key distribution can provide information-theoretical secure communication, which is now heading towards building the quantum secure network for real-world applications. In most built quantum secure networks, point-to-multipoint (PTMP) topology is one of the most popular schemes, especially for quantum access networks. However, due to the lack of custom protocols with high secret key rate and compatible with classical optical networks for PTMP scheme, there is still no efficient way for a high-performance quantum access network with a multitude of users. Here, we report an experimental demonstration of a high-rate 16-nodes quantum access network based on passive optical network, where a high-efficient coherent-state PTMP protocol is novelly designed to allow independent secret key generation between one transmitter and multiple receivers concurrently. Such accomplishment is attributed to a well-designed real-time shot-noise calibration method, a series of advanced digital signal processing algorithms and a flexible post-processing strategy with high success probability. Finally, the experimental results show that the average secret key rate is around 2.086 Mbps between the transmitter and each user, which is two orders of magnitude higher than previous demonstrations. With the advantages of low cost, excellent compatibility, and wide bandwidth, our work paves the way for building practical PTMP quantum access networks, thus constituting an important step towards scalable quantum secure networks.