Quantum repeaters on the way from the laboratory to practical application

Quantum technologies, including quantum communication, are among the key technologies of the future. “To realize quantum networks and, in the long term, a complex quantum internet, quantum repeaters are indispensable,” says Prof. Peter Michler, head of the Institute for Semiconductor Optics and Functional Interfaces (IHFG) at the University of Stuttgart. The German government’s High-Tech Agenda plans to demonstrate the technology of a first quantum repeater by 2028, and the “Technologies and Demonstrators for Quantum Repeaters” (TD.QR) project is designed to help achieve this goal.

Quantum repeaters are designed to enhance the security of critical infrastructures and enable new applications, such as securely networking remote quantum computers or bridging longer distances between nodes in the quantum internet. Researchers have long been working on these technologies, protocols, and concepts for this new component and its practical implementation. “With our new TD.QR project, we are now taking a decisive step further by conducting experiments outside of highly controlled laboratory environments to advance applications in fiber-optic networks,” explains Michler.

At the University of Stuttgart, the IHFG and the Institute for Functional Materials and Quantum Technologies (FMQ) are involved in the project. Peter Michler’s research group at the IHFG is focusing its experiments and tests on establishing eavesdropping-proof communication, while Prof. Stefanie Barz’s group at the FMQ is concentrating on linking quantum computers.

TD.QR stands for “Technologies and Demonstrators for Quantum Repeaters.” The Federal Ministry for Research, Technology and Space (BMFTR) is funding this new consortium project (January 2026 to March 2027) with approximately EUR 12 million. Coordinated by the University of Saarland, the partners University of Berlin, Julius Maximilians University of Würzburg, the Karlsruhe Institute of Technology (KIT), the Universities of Paderborn and Stuttgart, and the Technical University of Munich (TUM). The project builds on preliminary work from the joint project “Quantenrepeater.Net (QR.N)” and preceding consortia.

• Press release from the University of Saarland
• Project fact sheet “Technologies and Demonstrators for Quantum Repeaters (TD.QR)” (DE)
• Project fact sheet “Quantenrepeater.Net (QR.N)” (DE)

• Press release “Secure quantum applications for real-world networks”
• Press release "Record-breaking photons at telecom wavelengths — on demand"
• Press release "Milestone on the road to the ‘quantum internet’"
• Press release „Quantum repeaters for secure communication“