A Reconfigurable Relay for Polarization Encoded QKD Networks

TL;DR

This paper introduces a reconfigurable relay node for polarization-encoded QKD networks that adapts to various security needs and network configurations, extending operational distance and enabling P2MP topologies.

Contribution

It presents a novel relay architecture that switches between trusted and untrusted modes, centralizes SPDs, and simplifies user nodes for cost-effective and flexible QKD deployment.

Findings

Extends QKD network distance

Enables point-to-multipoint topologies

Simplifies user node design

Abstract

We propose a method for reconfiguring a relay node for polarization encoded quantum key distribution (QKD) networks. The relay can be switched between trusted and untrusted modes to adapt to different network conditions, relay distances, and security requirements. This not only extends the distance over which a QKD network operates but also enables point-to-multipoint (P2MP) network topologies. The proposed architecture centralizes the expensive and delicate single-photon detectors (SPDs) at the relay node with eased maintenance and cooling while simplifying each user node so that it only needs commercially available devices for low-cost qubit preparation.