Nokia Bell Labs, Deutsche Telekom T-Labs, and the Technical University of Munich have achieved a 1Tbps transmission speed over fibre in a field trial.
The trial showed that the performance of optical networks can be maximized when adjustable transmission rates are dynamically adapted to channel conditions and traffic demands.
The 1Tbps speed is close to the theoretical maximum information transfer rate of the channel, approaching the Shannon Limit of the fibre link.
The trial of Probabilistic Constellation Shaping uses quadrature amplitude modulation formats to achieve higher transmission capacity over a given channel to improve the spectral efficiency of optical communications.
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. PCS 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 fit the transmission channel, delivering up to 30% greater reach.