Alcatel-Lucent and BT have announced trial speeds of up to 1.4Tb/s with a record spectral efficiency of 5.7 bits per second per Hertz (b/s/Hz)on an existing core fiber connection.
This is believed to be the fastest speed ever achieved in commercial grade hardware in a real-world environment and is equivalent to transmitting 44 uncompressed HD films in a single second.
The field trial, conducted over an existing fiber link between the BT Tower in London and BT’s Adastral Park research campus in Suffolk, used a new ‘flexible grid’ infrastructure (Flexgrid) to vary the gaps between transmission channels, usually set at 50Gigahertz (GHz). By increasing the density of channels on the fiber, this approach achieved up to 42.5 percent greater data transmission efficiency compared to today’s standard networks.
The trial demonstrated that use of the Flexgrid approach can increase BT’s core network capacity using existing optical fibers, potentially reducing the expense of laying more fiber as bandwidth demands grow. This could allow BT to more easily scale its core network capacity to meet consumer and business demands for more bandwidth-hungry services such as streaming video, whilst more efficiently using its existing core fiber infrastructure.
The trial was conducted through the overlaying of an “Alien Super Channel” comprised of seven 200 Gigabits per second (Gb/s) channels bundled together to provide a combined capacity of 1.4Tb/s. By reducing the spectral spacing between the channels from 50GHz to 35GHz using the 400Gb/s Photonic Services Engine (PSE) technology on the 1830 Photonic Service Switch (PSS), spectral efficiency is enhanced by almost 43%. The 1830 PSS can be used as an optical extension shelf of the 7750 Service Router (SR) and the 7950 Extensible Routing System (XRS). Flexgrid is the key to creating high-capacity, spectrally efficient super channels. The super channel is “alien” because it operates transparently on top of BT’s existing optical network.