British Telecommunications has come up with a technique which, it claims, can use more of the 99.99% of optic fiber capacity that is currently unused, and is applying these changes to its infrastructure backbone. As a result of work at their R&D labs at Martelsham Heath, UK, the company reckons it can provide near- infinite bandwidth for its telecoms infrastructure. They use three key advances: Wave Division Multiplexing, optical switching, and optical amplification. Bell Laboratories, the research arm of Lucent Technologies Inc, managed to add 206 channels to a single fiber in a research project this year, as a demonstration of the potential capability of WDM which uses a number of different light frequencies (color) to add extra channels of information. WDM is already used in the US, where the longer distances involved make laying new fiber more expensive, British Telecommunications, which has been developing WDM for 15 years, has found the implementation expense too high. A current trial in East Anglia using this technology, called LEANet, is using eight channel WDM, as well as optical amplification which enhances signal speed, by not having the time delay of digital amplifiers, which wastefully convert light to digital and return the signal to light. When combined with WDM, optical amplification has the advantage of being able to amplify all the channels at the same time, and thus save further time, and further increase the bandwidth available. BT reckons it will be easier to manage their infrastructure using optical switching technology, which is currently used in their test 40Gbps SynchroLan, and they will be adding this technology to LEANet this year. Optical switching increases the ease of network management as signals can be re-routed, and damaged or overloaded parts of the network can switch to low-traffic routes in real time.