Researchers from the Universities of Bristol and Cambridge created a network that uses standard fibre-optic infrastructure but also features several quantum technologies, such as quantum key distribution, to support ultra-secure data transfers.
The researchers were able to transmit data between Bristol and Cambridge – a fibre distance of over 410 kilometres.
“This is a crucial step toward building a quantum-secured future for our communities and society,” said Dr Rui Wang, co-author and lecturer for future optical networks in the Smart Internet Lab's High Performance Network Research Group at the University of Bristol. “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.”
The research team demonstrated the capabilities of the network through real-world tests, including a quantum-secure video call, the transmission of encrypted medical data, and secure access to a distributed data centre — all of which were sent across the entire network.
At the heart of the system are two quantum technologies: encryption keys encoded in particles of light, making them ‘unhackable’, and quantum entanglement, where particles are so deeply linked that a change to one instantly affects the other, no matter the distance.
“Not only does it demonstrate the use of multiple quantum communications technologies, but also the secure key management systems required to allow seamless end-to-end encryption between us,” said co-author Adrian Wonfor of the University of Cambridge’s Department of Engineering.
The network, dubbed the UK Quantum Network (UKQN), has been a decade in the making and was developed with support from the UKRI’s Engineering and Physical Sciences Research Council.
The UKQN connects two regional quantum networks in Bristol and Cambridge via four long-distance fibre links and three intermediate nodes.
“This is a significant step in delivering quantum security for the communications we all rely upon in our daily lives at a national scale,” added Cambridge Professor Richard Penty, who led the Quantum Networks component of the broader Quantum Communications Hub initiative.
The successful demonstration puts the UK alongside countries like China and Spain, which have also trialled national quantum networks. But according to the researchers, this is the first time such a system has shown the ability to operate different quantum-secure technologies simultaneously across a major fibre route.
The project is set to continue, with the team behind it aiming to build out quantum networks from local systems, such as networks of quantum computers, to intercontinental links using satellites, enabling a truly global quantum internet.
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