TÜV NORD and Leibniz Universität Hannover jointly research tap-proof satellite communication

Cooperation relies on quantum mechanical methods to develop a new security standard

TÜV NORD and Leibniz Universität Hannover want to jointly develop a highly integrated quantum light source for the generation and exchange of so-called quantum keys (QKD - Quantum Key Distribution). The method uses the quantum phenomena of superposition and entanglement to share cryptographic keys between sender and receiver. With the new technology, tap-proof satellite communication with a range of more than 1,000 kilometres should be possible in the future. Together, the partners want to build a functioning QKD demonstrator during this time.

Personal data is constantly being transmitted digitally, to protect the privacy of users, but also of authorities and companies, from criminal access to passwords, email addresses and other data, scientists are researching new, tap-proof encryption methods.

With the advent of quantum computers, which have significantly higher data processing rates than classical computer systems, the digital encryption methods currently used can be decrypted and will no longer be secure in the foreseeable future. The Institute of Photonics (IOP) at Leibniz Universität Hannover and ALTER TECHNOLOGY, a company of the TÜV NORD GROUP, have agreed on a research cooperation to close this security gap.

The QKD method is based on so-called quantum light sources that can emit "entangled" photon pairs. Research into such photon pairs was recognised with the Nobel Prize in Physics in 2022. The quantum light source can be used to set up an eavesdropping-proof communication link: As soon as an eavesdropper tries to eavesdrop on the connection protected by QKD, this is detected due to the "entanglement" of the quantum keys used. "Currently, there are no stable efficient and integrated light sources for this," says Prof. Dr. Michael Kues, head of the Institute of Photonics (IOP) and board member in the Cluster of Excellence PhoenixD at Leibniz Universität Hannover.

Dr. Una Marvet, Head of Photonics Design Centre ALTER TECHNOLOGY, shares this assessment: ". Enabling secure quantum communication via satellite requires entangled photon sources that are compact and cost-effective as well as robust enough to perform reliably in the harsh environment of space. By jointly developing a fully integrated light source, we hope to produce a device that is compact, robust and scalable".

But until then, the researchers would still have to clarify numerous questions. "We need to investigate how heat affects the laser systems of the quantum source, how the light can be changed by filters and how we can couple the light from the system most efficiently," says Muhamed Sewidan, a PhD student involved in the research project. "An important task of universities is the transfer of knowledge and technology," says Kues and emphasises: "With such cooperation projects, doctoral students gain insight into industrial manufacturing and can thus pursue new approaches in research."

PhD student Sewidan will conduct the experiments on the design of the light source in the laser laboratory at Leibniz Universität Hannover Institute of Photonics  and continue his research at ALTER TECHNOLOGY's Seville and Glasgow sites. The company will then take over the product development.