Versatile Wavelength-Division Multiplexed Quantum Key Distribution Network Operating Simultaneously in the O and C Bands

TL;DR

This paper demonstrates a four-node quantum key distribution network using wavelength-division multiplexing in the O and C bands, enabling simultaneous secure key sharing with reduced costs and increased system compactness.

Contribution

It introduces a versatile, cost-effective WDM-based QKD network operating in multiple bands with shared components, enhancing scalability and practicality.

Findings

Successful simultaneous key distribution in O and C bands

Reduced system costs through shared decoding components

Enhanced network compactness and scalability

Abstract

Ongoing technological progress is accelerating the commercial and global-scale deployment of Quantum Key Distribution (QKD). Its ability to enable unconditionally secure communication is expected to be a key feature of future telecommunication networks, and practical demonstrations of QKD network implementations in real-world environments are crucial for ensuring reliable adoption. In this work, we demonstrate a four-node photonic QKD network that employs versatile and cost-effective wavelength-division multiplexing across three transmitters in the O and C bands to simultaneously distribute quantum-secure keys among all nodes. Specifically, the broadband central receiver node shares all optical and electronic decoding components, except for the single-photon detectors, across the three QKD links, significantly reducing system costs and enhancing compactness.