July 30, 2026 -- Quantum repeaters are considered a key technology for future quantum networks. One day, they could transmit quantum information and entanglement over long distances and therefore enable applications such as quantum-secure communication via quantum key distribution, distributed quantum computing, or networks of quantum sensors. Fraunhofer ISI’s new roadmap, compiled as part of the Umbrella Project for Quantum Communication Germany (SQuaD), compares different technology approaches and outlines the possible development steps leading to the commercial use of quantum repeaters in the future.

Technology development has always been closely tied to the available resources, from materials and energy to information and data. The rise of quantum technologies could result in an additional resource becoming more important in the future – quantum information. Researchers understand this as the storage, processing and transmission of information in quantum states, such as single photons or other quantum systems. Together with the principle known as entanglement, this opens up new opportunities for secure communication, distributed quantum computing, or high-precision sensor networks. Quantum repeaters are considered a promising approach for making this resource usable over long distances.

Unlike classical telecommunication signals, quantum information cannot be copied or amplified due to the principles of quantum mechanics. This limits the range and scalability of today’s quantum communication approaches. Quantum repeaters are intended to overcome this limitation by enabling distributed entanglement over greater distances. They are therefore considered an important prerequisite for powerful quantum networks in the future.

Applications range from secure communication to the “quantum internet“

The study ”Quantum Repeaters – A Technology Roadmap”, compiled by researchers at Fraunhofer ISI and Saarland University, is based on a comprehensive analysis of scientific literature, interviews and a roadmapping workshop with 22 experts from academia and industry. The objective was to document the current state of development, identify key challenges and indicate possible development pathways.

The authors view extending the range of quantum-secure communication via quantum key distribution as the most important short-term application. In the long term, quantum repeaters could also interconnect spatially separated quantum computers and therefore enable distributed quantum computing and the establishment of a so-called “quantum internet”. There are also potential applications for quantum sensor networks, such as high-precision clocks and measurement systems.

”In the future, quantum repeaters could play a similar role in quantum networks as classical repeaters do in today’s telecommunication networks, but based on completely different principles of physics”, explains Dr. Lukas Weymann of Fraunhofer ISI and the study’s lead author. ”In the long term, they will make it possible for us to access a novel resource, distributed entanglement. Which applications will ultimately emerge from this and how profoundly our technology landscape will change cannot be fully foreseen at present.”

Diverse technology approaches but no dominant platform so far

The roadmap shows that research is developing dynamically worldwide. At the same time, this field of technology is still in an early stage. At present, intensive research is taking place on different hardware platforms, including color centers in diamond, single trapped atoms and ions, warm and cold atomic ensembles, rare-earth-ion-doped crystals, or semiconductor quantum dots.

A key finding of the analysis is that no single platform has clearly emerged as the dominant one to date. Instead, the different approaches each feature their own specific strengths and challenges, for instance in terms of storage time, efficiency, scalability or compatibility. The study therefore sees good reasons for continuing to pursue multiple technology pathways in parallel. Hybrid systems that combine different platforms could also become more important in the future.

First major demonstrations are expected before 2035

However, considerable scientific and technological challenges have to be overcome before applications become widely available. These include improving efficiency and storage time, increasing transmission rates, integrating the technology into existing telecommunications infrastructures, as well as standardization and industrial scaling.

In the short term, the researchers expect additional demonstrations of individual components and network functions. Quantum repeaters, which transmit quantum information with lower losses than direct connections over long distances, could be demonstrated for the first time before 2035. This would be a major milestone on the road to future quantum networks. In the long term, demonstrations of applications such as networks of distant quantum computers or global quantum networks are expected.

”There is still a long way to go from today’s laboratory demonstrations to commercially usable quantum repeaters,” says Lukas Weymann. ”However, the advances made in recent years show that the field is developing enormous momentum. To fully exploit this potential, we need a prolonged phase of diverse research and close cooperation between science, industry and policymakers. There are already promising basic conditions for successful technology transfer from basic research to marketable applications: Germany’s High-Tech Agenda sets ambitious policy goals, and a quantum ecosystem comprising research institutions, startups and businesses has established itself both nationally and across Europe. We should continue to build on this.”