Ultra-high bandwidth quantum secured data transmission

TL;DR

This paper demonstrates the first successful integration of quantum key distribution with high-bandwidth classical data over existing fibre optic networks, achieving 200 Gb/s over 100 km and suggesting feasibility for 10 Tb/s over 50 km.

Contribution

It introduces an optimized wavelength division multiplexing scheme enabling coexistence of QKD with 100 Gb/s data, significantly advancing practical quantum-secured communications.

Findings

QKD can operate alongside 100 Gb/s data over the same fibre.

Achieved 200 Gb/s quantum encryption over 100 km.

Feasibility of combining QKD with 10 Tb/s data over 50 km.

Abstract

Quantum key distribution (QKD) provides an attractive means for securing communications in optical fibre networks. However, deployment of the technology has been hampered by the frequent need for dedicated dark fibres to segregate the very weak quantum signals from conventional traffic. Up until now the coexistence of QKD with data has been limited to bandwidths that are orders of magnitude below those commonly employed in fibre optic communication networks. Using an optimised wavelength divisional multiplexing scheme, we transport QKD and the prevalent 100 Gb/s data format in the forward direction over the same fibre for the first time. We show a full quantum encryption system operating with a bandwidth of 200 Gb/s over a 100 km fibre. Exploring the ultimate limits of the technology by experimental measurements of the Raman noise, we demonstrate it is feasible to combine QKD with 10 Tb/s of data over a 50 km link. These results suggest it will be possible to integrate QKD and other quantum photonic technologies into high bandwidth data communication infrastructures, thereby allowing their widespread deployment.