High-key-rate Fully-Passive Quantum Access Network with Thermal Source

TL;DR

This paper presents a fully passive quantum access network using passive state preparation, achieving a record key rate of 19.48 Mbps and compatible with classical optical networks for high-speed, stable quantum communication.

Contribution

It introduces a novel PSP-QPON protocol extending passive quantum key distribution to multi-point networks with high key rate and stability, compatible with existing optical infrastructure.

Findings

Final key generation rate up to 19.48 Mbps per network unit.

Extends PSP-CVQKD from point-to-point to multi-point networks.

Compatible with classical optical communication infrastructure.

Abstract

To accommodate classical communication systems with progressively increasing transmission rates, quantum access networks (QAN) have undergone systematic and protocol-level optimizations in recent years, where quantum passive optical network (QPON) architectures are gaining significant attention due to their simple structure. It is challenging for the previous QAN based on active protocols or Stokes operator coding protocols to achieve high-speed linear modulation with high extinction ratio and stability under practical conditions. In this work, we propose and experimentally demonstrate a downstream fully passive quantum access network protocol using passive state preparation (PSP) with free-space and single-mode fiber hybrid channels, and the final key generation rate is up to a record-breaking 19.48 Mbps per quantum network unit. The proposed PSP-QPON scheme extends the scope of PSP-CVQKD from point-to-point to point-to-multi-point networks, which enables high-key-rate, high-stability, and low-resource-consumption implementation. Moreover, the network channel in this experiment is fully compatible with access networks in classical optical communications, which allows integration with existing optical infrastructure without the need for additional modifications, providing a promising solution for local area network quantum access network at home or a mobile terminal.