QuNET - secure, quantum-based communication networks
QuNET - secure, quantum-based communication networks
Quantum key distribution via satellite
The mission of QuNET is to make the communications of the future secure against eavesdropping and tampering.
The QuNET (Quantum Network) research initiative was founded in 2019 and is scheduled to run for seven years. Its goal is to use various technologies to create the foundations and in-house expertise for tap-proof, quantum-based communication networks in Germany and Europe, thus laying the foundation for secure communications of the future. It is also intended to lead the way for a future "quantum Internet." This is because the transmission of quantum states via optical fibers or free beams can also be used to efficiently interconnect quantum computers. The resulting network components must support various protocols and technologies in order to provide the necessary flexibility for future developments.
DLR is working on practical solutions for satellite-based quantum communication to securely and efficiently distribute keys over long distances. In optical fiber, this is only possible over a few 100 kilometers. Quantum encryption via satellite, on the other hand, enables arbitrarily larger distances on Earth.
QuNET - Empfangs-Terminal
Das Empfangs-Terminal, das unter Forschern auch Bob-Terminal genannt wird, empfängt und misst die Quantenzustände. In der Freistrahlübertragung werden die Wellenfronten der Quantenzustände durch die turbulenten Luftschichten in der Atmosphäre verzerrt. Mit Hilfe modernster Technik, der sogenannten Adaptiven Optik, werden die Wellenfrontverzerrungen erkannt und in Echtzeit durch deformierbare Spiegel kompensiert.
Das Sende-Terminal, das unter Forschern auch Alice-Terminal genannt wird, sendet Licht im optischen Wellenlängenbereich für die Quantenkommunikation. Dieses weltraumtaugliche Terminal ist für den Einsatz auf Satelliten optimiert.
Satellitenbasierte Quantenkommunikation soll die sichere und effiziente Vereinbarung von Schlüsseln über große Distanzen hinweg ermöglichen. In der Glasfaser ist dies nur über wenige 100 Kilometer möglich. Die Quantenverschlüsselung via Satellit hingegen ermöglicht beliebig größere Distanzen auf der Erde.
The DLR Institute of Communications and Navigation looks back on more than 20 years of research and groundbreaking results in the field of free-space optical data transmission. For QuNET, the scientists contribute their expertise in satellite-based quantum communication and are responsible for the free-space communication channel in which quantum states are transmitted between satellites and Earth. The signal quality and transmission efficiency requirements are among the major challenges. The satellite system will be equipped with various quantum sources to ensure optimal connectivity to a heterogeneous quantum network. This includes, for example, single photon sources, entanglement sources, or differently constructed transmitter modules for quantum key distribution.
When transmitting quantum states, it is important to achieve the highest possible signal quality. For this reason, the satellite-side transmitting and ground-side receiving optics must be designed in such a way that the quantum states are transmitted with as little interference as possible and the beam alignment can be made extremely precise. DLR's research also includes detailed channel characterization to quantify its influence on state transmission.
