Breaking the information speed limit

Faster information flow has been a permanent human quest since the first hill-top beacons were lit. Now, in the digital era, researchers want to boost data to speeds of 40Gbit/s across entire optical networks. They want to eliminate the bottlenecks and distortions that come from current electronic technologies.

'Optical fibre technology has revolutionised networks by providing high-capacity, point-to-point links but they are interconnected with nodes based on electronic processing, which has speed limits,' said Dr Benn Thomsen of

. Replacing the processors with optical switches would remove these barriers, but they have their own problems - the signals get distorted and implementing the switches efficiently is not easy.

So Thomsen aims to identify and verify suitable optical technologies for processing in dynamic networks to reduce the signal distortions. 'I'll be studying non-linear devices, such as semiconductor optical amplifiers (SOAs) and analysing their transfer functions,' he said. 'We need to know if we are able to deal with their less-than-ideal transfer functions in optical network applications.'

While these devices have been studied before, they have usually been considered discretely, which is far from how they would be used in a real network. So Thomsen plans to build a test bed that will emulate the varying distortions and length scales that are found in a realistic dynamic network. This will be used to analyse how the devices perform at reducing the distortions found in dynamic networks when signals are routed over different paths.

'We will be able to reconfigure the physical network on the fly and analyse what happens to the signal,' said Thomsen. This test-bed is designed to be independent of the particular network architecture so that the research focuses on solving the principal physical issue of mitigating the increased and variable levels of signal distortion that arise in dynamic networks.

The five-year project, which begins in October, has been awarded £163,564,000 of government funding and is being done in close collaboration with the EU-funded NOBEL project which includes all the major European telecoms companies. If Thomsen can identify and verify suitable technologies he hopes the devices will perform the switching and signal cleaning. 'My hope would be that at the end of the project we can test such device in a real network.'