DLR demonstrates airborne quantum communication link

Summary Points: 

• The experiment was conducted under Germany’s QuNET initiative for quantum-secure communications.
• The team successfully transmitted individual photons, tested ion traps, and performed multiple QKD trials.
• Quantum key distribution could enable secure, long-distance communication resistant to eavesdropping.

COLOGNE, Germany - The German Aerospace Center (DLR) announced it has demonstrated the ability to transmit photons from multiple quantum channels between an aircraft and a ground station, sending photons to an ion trap, and testing several methods for quantum key distribution (QKD) as part of its research into airborne quantum communications. 

The experiment was part of the QuNET initiative, a national program focused on developing quantum-secure communication. By using photons - particles of light - scientists can create quantum encryption keys that could make future communications resistant to eavesdropping. The same technologies may also form the foundation for a quantum internet capable of linking quantum computers around the world.

The research team included experts from the German Aerospace Center, the Max Planck Institute for the Science of Light (MPL), Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), the Fraunhofer Institute for Applied Optics and Precision Engineering (IOF), and the Fraunhofer Heinrich-Hertz-Institut (HHI). Their results were presented to Germany’s Federal Ministry of Research, Technology and Space (BMFTR), which sponsors the QuNET program.

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Secure communications

Quantum key distribution is expected to play a central role in protecting sensitive communications for governments, public agencies, and critical infrastructure, as well as in safeguarding personal data in the years ahead.

"We are developing practical methods for satellite-based quantum communication that allow quantum states to be transmitted across long distances and used to generate secure keys," said Florian Moll of the DLR Institute of Communications and Navigation. "In fiber networks, this can only be achieved over a few hundred kilometers, but quantum encryption via satellite can cover any distance on Earth. To span those distances, satellites, aircraft, and other mobile platforms will be key components of tomorrow’s quantum networks."

The flight trials used a Dornier 228 research aircraft operated by DLR’s Flight Experiments facility. Engineers equipped the aircraft with an optical communication terminal, turning it into a mobile node that could establish a quantum link with a ground station. The ground receiver was housed in a mobile container known as the QuBUS, designed and provided by the Fraunhofer IOF.

DLR notes that handling single photons is extremely challenging. For reliable quantum communication, photons must be generated with exceptional precision and detected clearly, even in the presence of strong environmental interference. Accurate wavelength calibration is also critical to achieving optimal results.