In collaboration with partners from the space industry, scientists at ETH Zurich have successfully demonstrated terabit optical data transmission through the air.

This breakthrough could significantly reduce the expense of undersea cables and enable faster backbone connections via near-earth satellite constellations.

The project partners conducted a test between the alpine mountain peak, Jungfraujoch, and the Swiss city of Bern, achieving high-data transmission over a free-space distance of 53km. This test route presented challenging conditions due to factors such as diverse turbulence, the water surface of Lake Thun, the densely built-up Thun metropolitan area, and the Aare plane.

Internet connections via satellite are not new, but they typically use radio technologies with slower microwave transmission. On the other hand, laser optical systems operate in the near-infrared range and can transport more information per unit of time.

This optical data transmission project, conducted in a European Horizon 2020 framework, is an example of academic-industry cooperation. Thales Alenia Space, a French company, is specialised in targeting lasers with centimetre accuracy over thousands of kilometres in space. Another French company, ONERA, is specialised in MEMS-based adaptive optics, which deals with the impact of shimmering in the air on optical communication. ETH Zurich contributed with cutting-edge methods of signal modulation.

ETH professor J