Boosting the speeds of satellite communication for next-generation broadband networks is a big priority for the space community. ADVA and the German Aerospace Center (DLR) announced this week a new data transmission record for free space (no fiber optics) laser communications. The trial succeeded in transmitting 13.16 Tbps of data over a simulated geostationary (GEO) satellite link.
“This trial is a significant milestone in the evolution of stable, high-speed communication via satellite. It’s showing the industry that multi-Terabits of data can be transported every second via satellites using free-space laser communications,” said Christoph Günther, director, DLR Institute of Communications and Navigation. “One of our core aims is helping to achieve global connectivity and this test is a big part of realizing that goal. Through a lot of close collaboration between the DLR and ADVA teams, we’ve been able to demonstrate that this approach is not only feasible but that it’s ready to be used to transmit the enormous amounts of data needed for tomorrow’s users. Setting this benchmark brings high-speed broadband for everyone a step closer to reality.”
DLR developed the free-space terminal technology while ADVA’s FSP 3000 CloudConnect platform handled the optical-to-data links. The link moved data through the air over a distance of 14.45 kilometers and was designed to represent the challenges of moving data between the ground and a satellite over 22,000 miles above the Earth. “Atmospheric turbulence in the demo was “equivalent to that experienced in a worst-case scenario between ground and geostationary satellites,” according to the ADVA press release. For free-space laser communication, a dynamic atmosphere with clouds, moisture, and particulate matter is an extreme challenge; it’s the difference between sailing on the ocean verses a cup-of-water environment provided on a glass fiber.
The 13.16 Tbit/second is nearly eight times over DLR’s previous data record. Each wavelength on the laser carried 200 Gbit/second payload data using dual-polarization 16QAM and strong soft-decision forward error control. On a terrestrial connection, ADVA’s FSP 3000 CloudConnect platform can deliver up to 38.4 Tbit/s duplex capacity per fiber pair at up to 600 Gbit/sec duplex per wavelength.
On a deeper dive, there are a couple of significant bits of information here. DLR’s use of a simulated geostationary link fits into an “Old Space” model of larger satellites in a fixed position relative to a point on the Earth’s surface. The German space agency is already operating laser communication gear in a much more challenging environment, moving radar and multi-spectral imagery between low Earth orbit (LEO) Copernicus Sentinel satellites, geostationary satellites akin to NASA’s TDRS relay network, and European ground stations at about 1.8 Gbps on the laser side.
Will laser communications be viable for GEO satellites? Most of the work in “New Space” is applying laser to satellite cross-connections in large LEO constellations being proposed and built by companies such as LEOsat, with in-space network links moving data between satellites while more traditional radio frequencies are used for satellite-ground segments. Using laser as a primary means of satellite-ground communication is interesting since satellite operators would be able to move data at terabit speeds without having to compete for spectrum licenses and worry about “landing rights” in multiple countries.
Finally, ADVA’s participation in the DLR test is another cross-over between space and IT worlds. While all indications are this is a customized lab project, ADVA demonstrated it has the capabilities to support production GEO free space laser gateways in the future. The bigger challenge will be for service providers to make a business case for GEO laser satellites.
It might also be interesting to see if ADVA makes some moves from data center-sized optical gear to flight-qualified satellite hardware. A growing number of LEO broadband constellations means there will be demand for more optical routing gear into orbit in the future.
