Researchers from the Universities of Bristol and Cambridge, operating as part of the UK's Quantum Network and Quantum Communications Hub, have demonstrated long-distance quantum communication between their two cities using quantum key distribution, including a live video conference. Their results were presented recently at Optical Fiber Communications 2025 in San Francisco.
This is the latest practical demonstration of quantum communication, which enables far higher security than any current encryption technique. That's because quantum systems famously change when they're observed, meaning that eavesdroppers can't listen in without being detectable themselves.
This may initially be most relevant for particularly sensitive information such as the medical records transmitted in this demonstration, but it seems possible that one day quantum-secure communication will become available for more everyday data as well – a real quantum internet.
In particular, as described in the article, this improved security can be implemented using existing optical fibres (albeit ideally high-quality ones), and several countries are working on implementing large-scale quantum networks like the UK's, including satellite links.
While quantum computing tends to get the most coverage and public interest, there are plenty of other areas of quantum technology that look set to impact our lives, and secure quantum communication is certainly one to keep an eye on!
The researchers demonstrated the capabilities of the network via a live, quantum-secure video conference link, the transfer of encrypted medical data, and secure remote access to a distributed data centre. The data was successfully transmitted between Bristol and Cambridge – a fibre distance of over 410 kilometres.
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