Quantum communications are at the forefront of providing unparalleled security against potential threats posed by quantum computers. These advanced systems have the capability to break through current cryptographic methods, making traditional security measures obsolete.
The development of quantum networks has been a global effort, with significant progress seen in countries like China, Spain, and the UK. China has established a massive 4,600-kilometer network connecting cities through a combination of fiber optics and satellite technology. In Madrid, a smaller network with nine nodes has been implemented to securely share data using 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 trials have taken place in Singapore, Italy, and the USA.
Despite these advancements, there has been a lack of a large-scale, long-distance network that combines QKD, entanglement, and regular data transmission. However, a breakthrough has been made by a team from the Universities of Bristol and Cambridge in the UK.
The team successfully demonstrated the UK’s first long-distance quantum-secured video call and ultra-secure data transfer over a quantum communications network spanning 410 kilometers between Bristol and Cambridge. This network utilizes two QKD schemes: encryption keys embedded in light particles and distributed entanglement of quantum particles.
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The successful demonstration included a quantum-secured video call, encrypted medical data transfer, and remote access to a distributed data center. This achievement marks a significant milestone in integrating long-distance quantum-secured technologies with traditional communication infrastructure.
The experiment highlights:
- The potential of quantum networks to incorporate various quantum-secure approaches alongside conventional 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 step towards providing quantum security on a national scale, paving the way for a future quantum internet that connects nodes and devices through entanglement and teleportation.
- Highlighting the UK’s expertise in quantum networking technology and setting the stage for the development of resilient communication systems for the future.
The team’s future plans include continuing their work through the EPSRC-funded Integrated Quantum Networks Hub project. This initiative aims to develop quantum networks at various scales, from connecting local quantum processors to establishing national and global 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)
