Typical optical fibres consist of thin, solid glass wires. Tweaking the design could allow them to carry more data over longer distances.Credit: Phillip Hayson/Science Photo Library
A new type of hollow optical fibre promises to boost the amount of data that can be carried in each glass strand, and to do so over longer distances. This could help to make telecommunications systems faster and more efficient.
The design, described in Nature Photonics on 1 September1, replaces the hair-thin wire of solid glass that typical fibres are made from with a system of glass ‘straws’, in which five small cylinders, each containing two nested cylinders, are attached to the inside rim of one main cylinder. The diameter of each tube is finely tuned in such a way that that the space can only accommodate light of certain wavelengths. This means that when a light pulse of an appropriate wavelength is sent down the hollow central gap, it will stay there, rather than escaping.
“We really think this could be transformative,” says co-author Francesco Poletti, a photonics and materials-science researcher at the University of Southampton, UK.
“If the new fiber can be manufactured and installed easily and proves to be durable, the result might be a faster, better classical Internet,” says Rod Van Meter, a quantum network engineer at Keio University in Tokyo.
Fibres that contain hollow glass tubes nested inside one another can prevent light from escaping.Credit: Prof Francesco Poletti and Dr Greg Jasion, University of Southampton
The fibres will be produced by a start-up company called Lumenisity, a spin-off from Southampton that was bought by Microsoft in 2022. A typical glass fibre is made by melting a piece of glass, then stretching it to produce a strand of the desired thickness. To manufacture their hollow fibres, the researchers start with a larger version of their design — measuring about 20 centimetres in diameter. The hollows are pressurized during stretching, so that the configuration stays the same as the whole structure becomes around 100 micrometres wide.
Making connections
Hollow optical fibres of various designs already exist and have found niche applications, for example, in connecting the many computing units in data centres, where speed is of the essence (light travels 45% faster through hollow, air-filled tubes than through solid glass). Van Meter calls the increase in speed “a dramatic change that people will pay a lot of money for”.
