Alphabet’s laser internet system sent 700TB of data with 99.9% uptime
Google’s parent company Alphabet is still experimenting with connecting remote towns to the Internet via laser beams. Today, the Alphabet “X Lab” moonshot shared an update on the Taara project, its experimental point-to-point optical communication system, often described as “optical fiber without fiber”. The company built a functioning facility in Africa and blew up a 20 Gbit / s link for about 5 km across the Congo River to a city of millions of people, reducing the cost of access to Internet for them.
The Taara laser beam bridges the gap between Brazzaville in the Republic of the Congo and Kinshasa in the Democratic Republic of the Congo, which lie on either side of the Congo River. Brazzaville has decent internet, but because no one wanted to run a fiber line across the deepest and second fastest river in the world, Kinshasa uses a fiber line that runs 400 km about the river, and the Internet is five times more expensive. Alphabet’s 20Gbps commercial link has been up and running for 20 days now, and the company says it served nearly 700TB of data during that time, with 99.9% uptime.
Taara was born from the “Loon” Internet balloon project launched in 2017. Originally, Google built flying cell towers to teleport the Internet from the sky (over RF), but for balloon-to-balloon transport the company planned communications by laser beam. Space X has just started doing something similar by equipping its Starlink satellites with space lasers for intra-satellite optical communication. One of the advantages of sky and space based laser communication is that not much can interfere with a point-to-point optical beam. Lasers on the ground have more interference to consider, as they have to deal with just about anything: rain, fog, birds and once, according to Alphabet’s blog post, “a curious monkey.”
A big part of the Taara project was to solve all of these ground interference problems. Taara detonates a laser in a 45 degree mirror, resulting in a laser that rotates 90 degrees and shoots from the front lens. The mirror is movable, allowing both ends of Taara to make small adjustments. Alphabet says, “To bond, Taara’s terminals search for each other, detect each other’s beam of light, and lock together like a handshake to create a high-bandwidth connection.” With adjustable beams, Alphabet claims to have been able to handle haze, light rain and birds without downtime.
Like any other method of internet connectivity, Alphabet claims that wireless optical communication is not a universal solution, but it can fill in the gaps where faster, more reliable methods (like fiber) are not feasible. With local weather being the main factor of interference, the company produced a color-coded world map where it indicates that the technology will be viable. Strangely, the red is here Well and indicates that Alphabet expects to achieve 99% uptime with a link in this area.