Scratching the Way to a Faster Internet

New Scientist, 5 Nov 2005 Scratched glass could boost data speeds through fibre-optic cables, improving internet bandwidth. Light signals in a fibre-optic network are regularly cleaned up and retransmitted. This is done by electronic circuits, but electrical impulses travel much slower than light, creating a bottleneck. Now a team from the University of Sydney and the Australian National University in Canberra has created a thumbnail-sized filter out of glass etched with about 10,000 scratches, spaced roughly a micrometre apart. The material is doped with sulphur, selenium and tellurium, which broadens the spectrum of frequencies of pulses passing through. The more powerful the pulse, the more it is broadened, so the signal is changed to a greater degree than the noise, which the scratches then filter out.