Nothing moves faster than light in a vacuum, but large volumes of data can now travel at 99.7 per cent of this ultimate speed limit.

In glass optical fibres, light travels 31 per cent slower than in a vacuum. Hollowing them out so that most of the light travels through air speeds things up. But these hollow fibres are a poor replacement as light scatters at the glass-air interface, limiting the number of wavelengths, and therefore the volume of data, transmitted at once.

Now Francesco Poletti and colleagues at the University of Southampton, UK, have made fibres with an ultra-thin glass rim, enabling a much wider band of wavelengths to travel at high speed at once. The team’s record is a 73.7 terabit per second transmission over 310 metres, a 15,000-fold increase over ordinary hollow fibres.

“Previous fibres either have higher bandwidth but high loss, or lower loss but narrower bandwidth,” says Poletti. “We’ve achieved both in the same fibre.”

Journal reference: Nature Photonics, DOI: 10.1038/nphoton.2013.45