Tubes of glass

The idea of using glass tubes to transmit information dates back to the 1920, with experiments to send images through thin fibres.

But the outcome was disappointing. Whenever the tubes touched, or their surface was scratched, the light "leaked" away.

In 1966, Kao, a young Shanghai-born engineer working at the Standard Telecommunication Laboratories (STL) in Harlow, near London, determined that the main problem lay with iron ions in the glass, which absorbed and scattered the light.

His solution was fused silica, a glass-making process that would be without the impurities.

The difficulty, though, was that fused silica has a highly melting point, and it was tough to make and manipulate such materials on a commercial scale.

Four years afterward, the technical breakthrough came at Corning Glass Works in the United States.

Optical fibre was born, and has been continuously improved since then, thanks to chemical "doping" in the manufacturing process to help mitigate light loss.

Today, a pulse sent down a modern optical fibre loses less than five percent of its light after one kilometre.

The first transatlantic fibre-optic was installed in 1988, but the real bounty of this technology started to be realised in the late Nineties, when cheap lasers, light repeaters and computing power to handle large packets of data became available.

Kao was "a revolutionary," said Sir Peter Knight, senior principal at Imperial College London.

"He had already spotted the communications opportunities, and therefore the great distances light could travel, while others were still thinking in metres."