NTT Demos 14 Tbit/s

TOKYO -- Nippon Telegraph and Telephone Corporation has successfully demonstrated the ultra-large capacity optical transmission of 14 Tera bits per second (Tera is one trillion) over a single 160 km long optical fiber. The value of 14 Tbps (111 Gbps x 140 ch) greatly exceeds the current record of about 10 Tbps and so claims the record of the world's largest transmission capacity.

This result was reported as a post deadline paper in the European conference on optical communication (ECOC) that was held in Cannes, France from September 24 to 28.

The present core optical network is an optical transport network with about 1 Tbps capacity. Based on the wavelength-division-multiplexing (WDM) of signals with the channel capacity of 10 Gbps, it uses optical amplifiers with the bandwidth of about 4THz. The data traffic has been doubling every year due to the rapid spread of broadband access. We must lower the cost and raise the capacity of the core network while maintaining its reliability as the dominant communication infrastructure.

10 Tbps transmission over a single optical fiber has been achieved in the laboratory. However, it was necessary to use linear amplifiers that covered two or three amplification bands because of the limited range of existing amplifiers, and this multi-band configuration is not cost-effective. To increase the transmission capacity, we had to achieve two goals simultaneously: WDM transmission with high spectral efficiency and optical amplifiers with greatly enlarged bandwidth.

NTT Group (NYSE: NTT)