Back in November 2016, researchers at the German Aerospace Center (DLR) broke the world record in optical free-space data transmission with a data rate of 1.72 Tbit/s. On May 10, they raised the bar to a new record high in a trial between a ground station in Weilheim and a mock satellite on the Hohenpeißenberg mountain: Working together with telecommunications supplier ADVA Optical Networking SE , they succeeded in transmitting 13.16 Tbit/s of data. The data was transmitted over a distance of 10.45 km, using 53 lasers at various frequencies with 50 GHz channel spacing (wavelength division multiplex).
Optical free-space transmission transports the large data streams between the Internet and satellites, in a similar way to fiber optic in terrestrial transport networks. The technology is therefore of massive significance for supplying broadband Internet services from satellites to rural areas that are not connected to a terrestrial broadband network. And the throughput is, indeed, tremendous: At the new world-record data rate, it would be possible to transmit every printed book in the world within about half a minute. This data rate would also be high enough to cope with the data traffic of 144 petabytes per day forecast for Germany in 2020.