British Researchers Advance Toward Cable-Free Optical Broadband

A UK-led study into ‘twisted light’ could be a significant move toward broadband at fibre-optic speeds, but without the need for cabling

British scientists have contributed to what they call a significant advance toward wireless optical broadband that would have a much higher capacity than today’s fibre-optic cables.

Credit: University of Glasgow
Credit: University of Glasgow

A team based in the UK, Germany, New Zealand and Canada carried out tests of a technique that involves ‘twisting’ photons by passing them through a hologram, giving them what’s called optical angular momentum.

The number of twists in the photons can be used to represent information in addition to the ones and zeroes carried by current optical networks, potentially meaning much higher bandwidth.

The technique can be used to transmit photons over cables, but the researchers investigated wireless techniques, which pose additional difficulties from interference.

Free-space optics

They examined the effects of turbulent air in a free-space link in Erlangen, Germany, that was 1.6km in length and passed over fields and streets.

The study’s thorough investigation of the effects of turbulent air on structured light is an important step toward making commercial systems viable, said Dr. Martin Lavery, head of the Structured Photonics Research Group at the University of Glasgow.

Lavery, lead author on the team’s paper, published in the journal Science Advances, said free space optical broadband could provide the bandwidth of fibre, without the requirement for physical cabling, making it ideal for developing countries, defence systems and high-density urban environments.

“In an age where our global data consumption is growing at an exponential rate, there is mounting pressure to discover new methods of information-carrying,” he stated. “This study takes vital steps forward in the journey towards high dimensional free space optics that can be a cheaper, more accessible alternative to buried fibre-optic connections.”

He said the findings would allow scientists to rethink approaches to channel modelling in adaptive optical systems.

Researchers participated from the Max Planck Institute for the Science of Light and Institute of Optics and the Universities of Otago, Ottawa and Rochester.

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