Quantum key distribution over a metropolitan network using an integrated photonics based prototype

TL;DR

This paper presents a high-speed, stable, integrated photonics-based QKD prototype suitable for metropolitan networks, demonstrating continuous operation over 4 km of fiber without manual adjustments.

Contribution

The work introduces a practical, stable, and scalable integrated photonics QKD system designed for real-world metropolitan deployment, eliminating the need for dispersion compensation.

Findings

Stable operation over 12 days without manual intervention

Continuous key exchange over 4 km of fiber

High-speed 1.25 GHz key distribution

Abstract

An industrial-scale adoption of Quantum Key Distribution (QKD) requires the development of practical, stable, resilient and cost-effective hardware that can be manufactured at large scales. In this work we present a high-speed (1.25GHz), field-deployable QKD prototype based on integrated photonics, that is consolidated into standard 19-inch rack compatible units. Through integrated photonics, the system prioritizes autonomous long-term stability in metropolitan settings. The architecture is further simplified by removing the need for chromatic dispersion compensation over metropolitan distances (below 100km). We demonstrate continuous key exchange over more than 4 km of metropolitan optical fiber, where the prototype maintained stable, uninterrupted operation across a measurement spanning more than 12 day-night cycles without manual intervention.