In a significant leap toward realising a future quantum internet, researchers in Germany have managed to send quantum-encrypted messages through a conventional fibre-optic telecoms network—marking a critical milestone in secure communications.
The experiment, carried out by Deutsche Telekom in partnership with the Fraunhofer Institute for Applied Optics and Precision Engineering, used existing fibre infrastructure to transmit quantum keys between users in Berlin and Bonn over a distance of 70 kilometres. Crucially, this was done without deploying any exotic or specially developed fibre—demonstrating that quantum communications may one day operate over today’s networks.
Quantum security in the real world
Quantum communication promises near-unbreakable security based on the laws of quantum mechanics. Unlike classical encryption methods that depend on complex algorithms (and can be cracked with sufficient computing power), quantum key distribution (QKD) uses the properties of photons to generate and exchange encryption keys. If anyone tries to intercept or tamper with the message, the quantum state of the particles changes, alerting users to a potential breach.
This real-world demonstration is significant because it blends quantum systems with conventional telecommunications technology. “We have achieved a milestone on the way to a secure European quantum internet,” said Claudia Nemat, Deutsche Telekom board member for Technology and Innovation. “It brings us closer to protecting sensitive communications from future threats, such as quantum computers capable of cracking today’s encryption.”
Why it matters
The looming rise of quantum computers, with their ability to perform certain calculations exponentially faster than today’s machines, poses a genuine threat to current encryption standards. Once powerful enough, they could decrypt vast volumes of secure communications—from financial data to national security information. Quantum key distribution offers a countermeasure, enabling encryption that is theoretically impossible to intercept without detection.
Until now, quantum communication has largely been confined to lab settings or highly customised networks. What makes this demonstration stand out is its practicality: it shows that quantum communication can piggyback on existing telecom infrastructure. That could make deployment faster and more cost-effective than previously imagined.
The Berlin-Bonn link
The demonstration connected two government facilities in Berlin and Bonn via Deutsche Telekom’s standard fibre-optic backbone. Over this network, researchers sent quantum keys using a QKD system developed by the Fraunhofer Institute. These keys were then used to encrypt and decrypt real messages—achieving end-to-end quantum-secure communication over a commercial network.
According to the Financial Times, this is the first time such a feat has been accomplished over a standard, long-distance telecoms network in Europe. It shows not just the technical feasibility of QKD but also its potential for scaling across national infrastructure.
Europe’s vision for a quantum future
This breakthrough aligns with broader European ambitions to build a secure quantum communication infrastructure. The European Union is currently investing in the EuroQCI (Quantum Communication Infrastructure) initiative, which aims to create a pan-European quantum network within the next decade. The technology demonstrated in Germany could form the backbone of that system.
The researchers emphasised that this is just the beginning. “We still need to scale up the technology and ensure interoperability between systems,” said representatives from the Fraunhofer Institute. However, the results offer compelling proof that the dream of a quantum-secure internet is not just theoretical—it is technically within reach.
What is next?
While quantum communication is still in its early days, this achievement shows tangible progress. Future developments will likely focus on expanding distances, improving stability, and integrating QKD into more of Europe’s digital infrastructure.
At the same time, questions remain about regulation, cost, and accessibility. Who will control quantum networks? How will governments and private industry cooperate to build them? And how can we ensure they remain open, secure, and resilient in the face of rapidly advancing technology?
What is clear is that quantum communication is no longer a laboratory fantasy. With this successful demonstration over Germany’s telecoms backbone, Europe is a step closer to a new era—where the secrets of tomorrow can remain safe, even in the face of quantum-powered threats.
