Alcatel-Lucent and BT achieved optical transmission speeds of up to 1.4 Tbps, with a record spectral efficiency of 5.7 bits per second per Hertz (b/s/Hz), in a trial last autumn over a 410 km fiber link between BT’s Adastral Park research campus in Ipswich and the BT Tower in London.
The field trial used a new "flexible grid: infrastructure (Flexgrid) to vary the gaps between transmission channels, usually set at 50 GHz, to a new spacing of 35 GHz by using the 400 Gbps Photonic Services Engine (PSE) technology on the 1830 Photonic Service Switch (PSS). Alcatel-Lucent said that by increasing the density of channels on the fiber, this approach achieved up to 42.5% greater data transmission efficiency compared to today’s standard networks. The 1830 PSS can be used as an optical extension shelf of the 7750 Service Router (SR) and the 7950 Extensible Routing System (XRS).
- During October and November of 2013, BT and Alcatel-Lucent successfully demonstrated a number of world-leading high-speed alien wavelength technical achievements, including a record spectral efficiency of 5.7b/s/Hz which is equivalent to fitting a 1Tb super channel in less than 200GHz spectrum.
- The trials were performed using production equipment that was software reconfigurable between 200Gb/s using 16 QAM modulation and 100Gb/s using QPSK modulation
- Alien Wavelengths allow telecom operators like BT to introduce new features and technology without the need to update the existing optical transport infrastructure
- Flexgrid maximizes the spectral efficiency of the installed fiber infrastructure, deferring the need to deploy costly new fiber infrastructure
- Trial and evaluation of the 1.4Tb/s alien super channel showed stable, error-free operation, when being transmitted with a mix of 40Gb/s and 100Gb/s native wavelengths. This was achieved for standard 50GHz sub-channel spacing and for flexgrid with sub-channel spacing down to 35GHz.