Jens Kruse

Recent years have seen tremendous progress in increasing distances for distribution of quantum states and quantum entanglement, most notably in quantum key distribution. Even though these advances point towards breaching 1000 km and more in the near future, true global connectivity for secure intercontinental quantum links will likely require the operation of trusted networks based on quantum repeaters. To overcome associated losses in even the best optical fibers on ground, operating repeater nodes in space to utilize low-loss inter-satellite links may prove to be the only viable strategy. Successfully deployed QKD experiments and quantum technology in space, brings this idea closer to realization. Nevertheless, conceptual designs [9, 10] and component development are still in their infancy and it will require extraordinary engineering achievements to materialize robust space-based quantum networks. Here, we present recent efforts at the German Aerospace Center (DLR) to investigate the realization of robust global quantum networks. We are developing a holistic approach which bundles expertise on the necessary components for space-based quantum repeaters, i.e. photon sources, quantum memories, optical links, laser terminals, and orbital simulations. From this, we derive a common set of requirements to push concrete technological implementation. The long-term goal of this project is to develop space-hardened components for successful operation of intercontinental space-based quantum networks.