Quantum Internet Research of Deutsche Telekom
Deutsche Telekom has been operating a quantum research lab in Berlin since 2023 and is leading EuroQCI’s PETRUS project. Last year, together with the company Qunnect, it was possible to achieve a transmission of entangled photons over a long distance with high accuracy.
This field experiment is an important milestone for the establishment of a quantum internet. A quantum internet is so important because it allows QuBit states to be transmitted over long distances and thus enable distributed quantum computing, for example.
In the experiment mentioned above, entangled photons could be transmitted over 30 km with an accuracy of 99% on a commercial optical fiber. The entangled photon distribution system, which automatically responds to environmental changes, has been continuously tested for 17 days with a 1% downtime.
A second additional field experiment aimed to demonstrate the coexistence of photons and classical signals. Here, the sensitive polarization-entangled photons in the O-band together with the intense classical signals of normal optical data traffic in the C-band could be dynamically routed over a distance of 60 km. Accuracies of over 92% were achieved, which is one of the longest high-fidelity entanglement distributions. https://arxiv.org/pdf/2504.08927
These demonstrations pave the way for commercial use in many future areas, such as highly secure quantum cryptography (QKD), but also for precise time synchronization and quantum sensing in the IoT environment.