Researchers hit 1.4 Tbps in real-world test

Researchers from Alcatel-Lucent and BT claim to have achieved transfer speeds of up to 1.4 Tbps across existing core fibre. With a spectral efficiency of 5.7 bits per second per Hertz, the researchers believe this is the fastest speed ever achieved in commercial-grade hardware in a real-world environment.

The trial was conducted over an existing 410 km fibre link between BT Tower in London and BT’s Adastral Park research campus in Ipswich, Suffolk.

The trial used ‘flexible grid’ Flexgrid infrastructure to vary the gaps between transmission channels, increasing the density of channels on the fibre and ultimately increasing data transmission efficiency.

The companies say the trial demonstrated that the Flexgrid approach could increase BT’s core network capacity using existing optical fibres, potentially reducing the cost of laying more fibre as demand for bandwidth grows.

The trial used seven 200 Gbps channels bundled together, providing a total capacity of 1.4 Tbps. Researchers reduced the spectral spacing between the channels from 50 to 35 GHz using the 400 Gbps Photonic Services Engine (PSE) technology on the 1830 Photonic Service Switch (PSS), thereby enhancing spectral efficiency by almost 43%.

Dr Tim Whitley, BT’s MD of Research and Innovation said: “BT has a long history of leading innovation in telecommunications, from the earliest days of the electric telegraph to today’s global fibre networks. These trials continue that tradition, as we work with Alcatel-Lucent to push the boundaries of fibre technology.”