The highest capacity of undersea cable in the world could be capable of speed 20% faster than thought theoretically possible. An experiment recently carried out using 16QAM modulation achieved a record transfer speed of 26.2 Tb per second on a 4,000 mile transatlantic cable that is jointly owned by Microsoft and Facebook. This represents 20% improvement on the originally thought capability of 20 Tb per second of each pair of the cable’s eight optic fibers, in accordance to the team of researchers from Infinera who conducted the test.
The speeds were displayed on the MAREA cable, which currently is the world’s highest capacity subsea cable with a theoretical capacity of 160 Tbps in total. The cable which was operated by Telxius, runs between Virginia Beach, Virginia and Bilbao in Spain, which have become popular sites for new data centers.
The importance of the announcement is two, firstly, according to Infinera, this new approach was demonstrated on an existing cable, thereby allowing for capacity upgrades without spending hundreds of millions to lay new cables. Secondly, the speeds were also displayed on a cable spanning such a long distance.
It definitely will take a while before we can see such speeds become commonplace. Even though 20 Tb per second transfer speeds were previously thought possible on the line, the current average transfer rate of the MAREA cable is just 9.5 Tbps. This implies that there are many more practical hurdles yet to be overcome.