Fiber-Optic Infrastructure Promises Speeds to 1.4 Tb/s

Recently, a novel approach to fiber-optic grid infrastructure showed the potential for more efficient channel building and faster data speeds without the deployment of more fiber. Developed by Alcatel-Lucent and British Telecommunications (BT), the flexible grid infrastructure—known as FlexGrid—increases the density of fiber channels. In doing so, it achieves up to 42.5% greater data transmission efficiency when compared to current networks. According to the companies, it can transmit the equivalent of 44 uncompressed high-definition (HD) films in just 1 sec.

In a field trial over an existing fiber link between the BT Tower in London and BT’s Adastral Park research campus in Suffolk, the FlexGrid infrastructure showed speeds to 1.4 Tb/s with spectral efficiency of 5.7 b/s/Hz. An “alien super channel,” which operates transparently on top of the existing optical network, was overlaid to provide a combined capacity of 1.4 Tb/s. It comprised seven 300-Gb/s bundled channels. Spectral spacing between channels from 50 to 35 GHz was reduced using 400-Gb/s Photonic Services Engine (PSE) technology on an 1830 Photonic Service Switch (PSS).

The demonstration showed stable, error-free operation when transmitting a mix of 40-Gb/s and 100-Gb/s native wavelengths as well as overall spectral efficiency of 43%. Aside from raising speeds for commercial-grade hardware in a real-world environment, Flexgrid has the potential to reduce the expense of laying more fiber as bandwidth demands grow. In 2013, BT and Alcatel-Lucent demonstrated other high-speed alien wavelength technologies to show spectral efficiency of 5.7 b/s/Hz—which is equivalent to fitting a 1-Tb super channel into less than 200 GHz of spectrum.