Universities Demo UK’s First Long-Distance Quantum-Secured Fibre Network

Researchers from the Universities of Bristol and Cambridge claim to have demonstrated the UK’s “first long-distance ultra-secure transfer of data over a quantum communications network” using “standard [single-mode] fibre optic infrastructure“. The test successfully transmitted a live quantum-secured video call over a distance of 410km (between Bristol and Cambridge).

Connections like this are extremely secure and intended to ensure that, should such a communication be intercepted along the way, the sender will be able to tell that the link has been tampered with, and the stolen photons cannot then be used as part of the key, thus rendering the data stream itself incomprehensible to a hacker.

The network itself harnessed two types of Quantum Key Distribution (QKD) schemes: “unhackable” encryption keys hidden inside particles of light; and distributed entanglement: a phenomenon that causes quantum particles to be intrinsically linked. The network then used these to demonstrate a live video conference link, as well as the transfer of encrypted medical data, and secure remote access to a distributed data centre.

This is said to be the “first time” that a long-distance network, encompassing different quantum-secure technologies such as entanglement distribution, has been successfully demonstrated (we’ve seen networks working over much longer distances, but not with both of these methods).

The demonstration was carried out using the UK Quantum Network (UKQN), established over the last decade by the same team, supported by funding from the Engineering and Physical Sciences Research Council (EPSRC), and as part of the Quantum Communications Hub project. This covers two metropolitan quantum networks around Bristol and Cambridge, which are connected via a ‘backbone’ of four long-distance optical fibre links spanning 410km with three intermediate nodes.

Report co-author, Dr Rui Wang (University of Bristol), said:

“This is a crucial step toward building a quantum-secured future for our communities and society. More importantly, it lays the foundation for a large-scale quantum internet—connecting quantum nodes and devices through entanglement and teleportation on a global scale.”

Sadly, we don’t get any details about the speed of this data connection, which would have been interesting to know. But the work, which was also supported by Toshiba, BT, Adtran and Cisco, still marks a significant step forward and toward building a national scale quantum secured network.

The team now plan to pursue this work further through a newly funded EPSRC project, the Integrated Quantum Networks Hub, whose vision is to “establish quantum networks at all distance scales, from local networking of quantum processors to national-scale entanglement networks for quantum-safe communication, distributed computing and sensing, all the way to intercontinental networking via low-earth orbit satellites“.