Alcatel-Lucent breaks optical transmission barrier

BOFFINS AT BELL LABS, the research arm of networking firm Alcatel-Lucent, have managed to set an optical data transmission speed record of more than 100Pb per second.kilometer.

To accomplish this feat the researchers combined 155 lasers, each capable of carrying 100Gbps of data, and offset the frequency of each beam to minimise interference, essentially boosting the performance of standard Wavelength Division Multiplexing (WDM) technology.

Those doing the maths will realise that this amounts to a network speed of 15.5Tbps, but data was successfully sent over this connection for a distance of 7,000km, giving the final bit per second.kilometers result - a standard measure for high speed optical transmission.

Not that a fine upstanding company like Alcatel-Lucent would ever suggest illegally downloading movies, music or games, but it does point out that this data transfer speed record is the equivalent of transferring 400 DVDs per second over 7,000 kilometres.

"There is no question that this record breaking transmission is a milestone in achieving the network capacity and speeds and a key step forward in satisfying the ongoing explosion in demand," said Gee Rittenhouse, head of Bell Labs Research.

To maintain the signal strength, repeaters were placed 90km apart, farther apart than the standard interval for long distance optical networks. The researchers also used advanced digital signal processors to boost capacity by increasing the number of light sources introduced into a single fibre yet still separate the light into its constituent colours when it reached its destination.

Although it's probably going to be a few years before this kind of technology is used to replace or upgrade the fibre optic undersea cables that are the fundamental intercontinental links in the backbone of the Internet, it does bode well for meeting the future needs of media hungry Internet users everywhere. µ