Frankfurter Allgemeine reports on the Fundamentals and Key Steps towards the future Quantum Internet:
In recent years, Quantum Networks have gained increasing importance in research. They are considered a foundation for future communication systems with novel security features, for example for critical infrastructures such as banks, data centers, and government authorities. In the long term, they could also enable the interconnection of Quantum Computers and Sensors or the development of a Quantum Internet. Quantum Teleportation plays a key role in this context as an important method of Quantum Communication. To test technologies developed in laboratories under real-world conditions, numerous test links have been established in Germany. These so-called testbeds are based on fiber-optic connections and primarily connect universities and research institutions. An overview of the testbeds collected as part of the umbrella project for Quantum Communication in Germany (SQuaD) can be found here. Beyond these dedicated test links, it is now also possible to reliably transmit Quantum Information within commercial urban data networks. The German daily newspaper Frankfurter Allgemeine reported on this in mid-August 2026.
The article focuses, among other things, on a joint experiment by Universität Paderborn, Deutsche Telekom, and the US-based network manufacturer Qunnect. The researchers succeeded in transmitting Quantum States over a roughly 30-kilometer section of Berlin’s fiber-optic network. This demonstrated that Quantum Teleportation can also be implemented under real-world conditions in existing communication networks. Of particular relevance is the possibility of transmitting quantum and classical communication signals over the same infrastructure. Even when conventional data signals were transmitted simultaneously, a high transmission fidelity was achieved.
The article also discusses Quantum Repeaters. They are considered a key component of future Quantum Networks. By using Quantum Teleportation and entangled Quantum States, they are intended to enable the reliable transmission of Quantum Information over longer distances. Unlike classical telecommunications signals, Quantum Information cannot be copied or amplified arbitrarily due to the laws of Quantum Mechanics. At the same time, transmission losses in fiber-optic networks increase with distance. Quantum Repeaters are intended to overcome these limitations by dividing long links into shorter segments.
Intensive research into these technologies is being conducted worldwide, including as part of the joint project Quantenrepeater.Net (QR.N). One example of progress in this field is a paper published in Nature Communications in November 2025 by researchers from the QR.N consortium in Stuttgart, Saarbrücken, and Dresden. The researchers demonstrated teleportation between photons from different semiconductor light sources. Using frequency conversion, the photons were converted to a common telecommunications wavelength for transmission. The results demonstrate that different sources can be interconnected for future Quantum Communication Systems.
It is likely to take several more years before high-performance Quantum Repeaters become available. Until then, Quantum Satellites could play an important role in transmitting Quantum Information over long distances. QUBE II, for example, is being used to test the transmission of Quantum Keys between a satellite and a ground station. In the longer term, satellite-based links could be combined with fiber-based Quantum Connections on the ground to establish Quantum Networks over long distances and eventually across continents. By combining different technologies, this could ultimately lay the foundation for a global Quantum Internet.
Source references: https://www.faz.net/aktuell/wissen/physik-mehr/lichtquanten-spuken-im-berliner-glasfasernetz-accg-201081639.html; https://arxiv.org/abs/2602.16613; https://www.nature.com/articles/s41467-025–65911‑9.pdf