Alcatel-Lucent Submarine Networks (ASN) and Nokia Bell Labs have achieved what they claim is a record transmission capacity of 65Tb/s over 6,600km of singlemode fibre.
An interesting point of comparison: the capacity of 65Tb/s is 13,000 times greater than the capacity that was available on the first undersea amplified transatlantic system installed in 1995.
The lab-based trial used submarine-grade, dual-band erbium-doped fibre amplifiers, and shows how a novel modulation format that the company described last month can be used to extend the capability of transoceanic cable systems to meet increasing data traffic demand.
That format is Probabilistic Constellation Shaping (PCS) technology, a technique that enhances the distance and capacity of high-speed optical transmission. Unlike traditional techniques whereby all constellation symbols are transmitted with the same occurrence, PCS intelligently reduces the occurrence of high-power symbols, thus providing more resilience to noise.
The latest submarine-oriented experiment follows a terrestrial trial. Nokia Bell Labs, Deutsche Telekom and the Technical University on Munich exploited PCS to achieve an improvement in reach of up to 30 per cent over Deutsche Telekom T-Labs’ optical testbed (see Nokia Bell Labs, T-Labs and Technical University of Munich test drive novel modulation scheme). Their work was reported at the European Conference on Optical Communications (ECOC) in Dusseldorf, Germany.
Olivier Gautheron, chief technology officer of ASN, said: "This new record is the latest in a long series of achievements by Alcatel-Lucent Submarine Networks over the past 20 years, with breakthroughs that have transformed long distance data transmission. It also underlines our strategic focus on R&D to raise the bar for undersea fibre-optic technology as our researchers continue to develop new solutions to help traditional and webscale operators cope with increasing requirements for speed, capacity and cost-effectiveness."
