Quantum communications offer unparalleled security against potential threats posed by quantum computers, which have the capability to compromise current encryption methods.
Researchers have been actively working on developing quantum networks globally. China, for instance, has established a 4,600-kilometer network connecting cities using fiber optics and satellites. In Madrid, a smaller nine-node network securely exchanges data through various Quantum Key Distribution (QKD) techniques. In 2019, Cambridge and Toshiba achieved record key rates, while Bristol successfully created a network enabling entanglement sharing in 2020. Similar experiments have been conducted in Singapore, Italy, and the USA.
Despite these advancements, no one had yet managed to create a large-scale, long-distance network that combines QKD, entanglement, and conventional data transmission.
A collaborative team from the Universities of Bristol and Cambridge has now achieved a significant milestone by demonstrating the UK’s first long-distance quantum-secured video call and ultra-secure data transfer via a quantum communications network. Spanning over 410 kilometers of fiber optic infrastructure between Bristol and Cambridge, this network employs two QKD schemes: encryption keys embedded in light particles and distributed entanglement, where quantum particles remain interconnected.
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The demonstration highlighted the network’s capabilities through a quantum-secure video call, encrypted medical data transfer, and remote access to a distributed data center. This breakthrough represents the successful integration of long-distance quantum-secure technologies such as entanglement distribution and regular data transmission.
The experiment highlights:
- The potential of quantum networks to incorporate various quantum-secure methodologies alongside traditional communication infrastructure.
- The utilization of the UK’s Quantum Network (UKQN), developed over the past decade with support from the Engineering and Physical Sciences Research Council (EPSRC) and the Quantum Communications Hub project.
- The integration of multiple quantum communication technologies, including secure key management systems for seamless encryption.
- A significant advancement in providing quantum security on a national scale, paving the way for a future quantum internet that connects nodes and devices through entanglement and teleportation.
- Showcases the UK’s expertise in quantum networking technology and sets the stage for the development of resilient communication systems for the future.
The team intends to further their research through a new EPSRC-funded initiative, the Integrated Quantum Networks Hub. This project aims to establish quantum networks of all sizes, from linking local quantum processors to creating national and international networks using low-earth orbit satellites for secure communication, computing, and sensing.
Journal Reference:
- R. Yang et al. A UK nationwide heterogeneous quantum network. Presented at the 2025 Optical Fiber Communications Conference and Exhibition (OFC)
