Digital transformation has – from industry 4.0 to healthcare applications – impacts on our society. Therefore, it is important to ensure data security as well as reliable and secure communication. By using fundamental laws of quantum physics, it is possible to create and distribute a shared secret key, which can be used for information-theoretically absolutely secure data transmission.
However, this technology is associated to considerable transmission losses so far, whereby the transmission distances are typically limited to less than 100 kilometers. The Fraunhofer Heinrich Hertz Institute and 23 other partners from research and industry are developing a solution to that problem within the scope of the project "Quanten-Link-Erweiterung" (Q.Link.X). A promising result of the project would be a functional quantum repeater, which binds the quantum signals of adjacent sections to enable larger transmission distances.