Alcatel-Lucent’s research and development division, Bell Labs, has successfully broken yet another record after it used 155 lasers (each operating at different frequencies and carrying 200Gbps of data over a 50GHz frequency grid) and an enhanced version of Wavelength Division Multiplexing (WDM) to send information at a staggering speed of 31 Terabits per second over a single 7200km long optical fibre cable. Previous experiments have been faster but only over shorter distances or by using a different type of fibre optic cable entirely

http://www.ispreview.co.uk/index.php/2013/07/alcatel-lucent-breaks-record-with-31tbps-over-a-single-fibre-optic-cable.html