Twisted light to boost fibre speeds

Network operators could squeeze far more data down fibres if research into the way light travels bears fruit.

Researchers at the Institute of Ultrafast Spectroscopy and Lasers in New York have developed a new way of mapping spiralling light, in a breakthrough that could illuminate untapped data channels in optical fibres.

“Until now, only the simplest form of light, the ground state, could be mapped and controlled,” said lead researcher Giovanni Milione. "Multiple higher channels in an optical fibre, which could be occupied by more complex light, were left sitting idle.

“This gives us a way to detect and measure a higher number of channels,” said Milione. “With such heavy traffic funnelled through a single channel, there is great interest in exploiting others that can be occupied by complex forms of light.”

With such heavy traffic funnelled through a single channel, there is great interest in exploiting others that can be occupied by complex forms of light

The discovery relies on polarisation to reveal how light travels within a laser beam, and being able to understand its movement could provide a wider capacity data beam.

“Being able to follow polarisation and other changes as light travels gives you insight into the material it travels through,” explains Milione. “This helps control the light and can essentially give a fingerprint of the fibre material being analysed.”

According to the researchers, complex light moves with both spin and orbital momentum, in a similar pattern to the moon as it spins on its axis and orbits the Earth.

Such light twists like a tornado as it travels through space in vector beams and vortices, which could carry more data than currently used light paths, the scientists believe.