Closing the gap to improve the capacity of existing fiber optic networks

A team of researchers working through Australia’s Centre for Ultrahigh Bandwidth Devices for Optical Systems (CUDOS) has developed data encoding technology that increases the efficiency of existing fiber optic cable networks. The researchers claim their invention increases the data capacity of optical networks to the point that all of the world’s internet traffic could be transmitted via a single fiber.

Compatible with existing networks, the data encoding technology involves making more efficient use of available data channels. Where existing networks transmit data with gaps between the channels, the new approach packs the data channels closer together, thereby allowing more lanes on the same super-highway.

To demonstrate the system, the researchers re-programmed a LCoS (liquid crystal on silicon) Wavelength Selective Switch (WSS) to make more efficient use of available data channels. A WWS is a network component that uses different wavelengths of laser light to combine (or multiplex) multiple digital data streams onto a single optical fiber.

The research team, which included Professor Arthur Lowery and Dr Liang Du of the Monash Department of Electrical and Computer Systems Engineering and Jochen Schroeder, Joel Carpenter and Ben Eggleton from the University of Sydney, managed to transmit a signal of 10 terabits per second (Tb/s) more than 850 km (528 miles) using the new technology.

That’s still well short of the 26 Tb/s data transmission speeds achieved by scientists at Germany's Karlsruhe Institute of Technology (KIT), but is over a far greater distance than the 50 km (31 miles) that team achieved.

Professor Lowry said that the switch could be used to squeeze signals into the gaps in data traffic that flows around large optical-ring networks between cities. "Importantly, new traffic can be squeezed into the fiber at any location and added to any ‘lane’ of the fiber freeway even between existing lanes,” he said. "Rather than laying hundreds of new parallel optical fibers to boost network capacity, we can make more efficient use of the existing network by tweaking the way data is transmitted over long distances."

“Our approach is so flexible, network operators could adjust capacity to respond to increased demand, for example from people following big sport events like the Olympics," added Dr Schröder.

The team believes the technology would allow existing infrastructure to cope with the rising demand for internet, which is expected to increase 1,000 fold over the coming decade, with minimal investment.