Nokia Bell Labs has squeezed 1Tbit/sec out of optical fibre, a new record in networking.
Working alongside Deutsche Telekom's T-Labs and the Technical University of Munich, the researchers pushed the transmission rate up to its theoretical maximum by using a different frequency depending on the requirements of each channel, a technique known as Probabilistic Constellation Shaping (PCS).
"PCS modifies the probability with which constellation points - the alphabet of the transmission - are used. Traditionally, all constellation points are used with the same frequency," Nokia Bell Labs said in a statement. "PCS cleverly uses constellation points with high amplitude less frequently than those with lesser amplitude to transmit signals that, on average, are more resilient to noise and other impairments. This allows the transmission rate to be tailored to ideally fit the transmission channel, delivering up to 30% greater reach."
The 1Tbit/sec achievement is close to the theoretical maximum transfer rate for the channel, called the "Shannon Limit". "The Shannon Limit was discovered in 1948 by Claude Shannon, Bell Labs pioneer and the 'father of information theory'," the statement explained.
The work is important as more and more data travels down pre-existing networks, with traffic doubling annually.
"Future optical networks not only need to support orders of magnitude higher capacity, but also the ability to dynamically adapt to channel conditions and traffic demand," said Marcus Weldon, president Nokia Bell Labs & Nokia CTO, in a statement.
"Probabilistic Constellation Shaping offers great benefits to service providers and enterprises by enabling optical networks to operate closer to the Shannon Limit to support massive datacentre interconnectivity and provide the flexibility and performance required for modern networking in the digital era."
