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New optical fibre sets world speed record

Macquarie University researchers and a team of Japanese, Dutch and Italian researchers have invented an optical fibre the thickness of a human hair which can carry the equivalent of more than 10 million fast home internet connections

Researcher academics at the Macquarie University along with a team of Japanese, Dutch and Italian researchers have set a new speed record for an industry-standard optical fibre, achieving 1.7 Petabits – the equivalent to the combined speed of 17 million NBN broadband internet connections – over a 67km length of fibre.

The fibre, which contains 19 cores that can each carry a signal, meets the global standards for fibre size ensuring that it can be adopted without massive infrastructure change. And it uses less digital processing, greatly reducing the power required per bit transmitted.

Macquarie University researchers developed a glass chip, which was essential to the creation of a 19-core optical fibre.

“We’ve created a compact glass chip with a wave guide pattern etched into it by 3D laser printing technology. It allows feeding of signals into the 19 individual cores of the fibre simultaneously with uniform low losses. Other approaches are limited in the number of cores and result in the loss of too much light, which reduces the efficiency of the transmission system,” says Dr Simon Gross from Macquarie University’s School of Engineering.

“It’s been exciting to work with the Japanese leaders in optical fibre technology. I hope we’ll see this technology in subsea cables within five to 10 years.”

Another researcher involved in the team, Professor Michael Withford from Macquarie University’s School of Mathematical and Physical Sciences, believes this breakthrough in optical fibre technology has far-reaching implications.

“The optical chip builds on decades of research into optics at Macquarie University,” says Professor Withford.

“The underlying patented technology has many applications including finding planets orbiting distant stars, disease detection, even identifying damage in sewage pipes.”

The fibre was developed by the Japanese National Institute of Information and Communications Technology (NICT, Japan) and Sumitomo Electric Industries Ltd. (SEI, Japan) and the work was performed in collaboration with the Eindhoven University of Technology in the Netherlands, University of L’Aquila in Italy and Sydney’s Macquarie University.

How optical fibres work

All the world’s internet traffic is carried through optical fibres which are each 125 microns thick (comparable to the thickness of a human hair). These industry standard fibres link continents, data centres, mobile phone towers, satellite ground stations and our homes and businesses.

Back in 1988, the first subsea fibre-optic cable across the Atlantic had a capacity of 20 Megabits or 40,000 telephone calls, in two pairs of fibres. Known as TAT 8, it came just in time to support the development of the World Wide Web. But it was soon at capacity.

The latest generation of subsea cables, such as the Grace Hopper cable which went into service in 2022, carries 22 Terabits in each of 16 fibre pairs. That’s a million times more capacity than TAT 8 but it’s still not enough to meet the demand for streaming TV, video conferencing and all our other forms of global communication.

“Decades of optics research around the world has allowed the industry to push more and more data through single fibres,” says Dr Gross.

“They’ve used different colours, different polarisations, light coherence and many other tricks to manipulate light.”

Most current fibres have a single core that carries multiple light signals. But this current technology is practically limited to only a few Terabits per second due to interference between the signals.

“We could increase capacity by using thicker fibres. But thicker fibres would be less flexible, more fragile, less suitable for long-haul cables, and would require massive reengineering of optical fibre infrastructure.”

“We could just add more fibres. But each fibre adds equipment overhead and cost and we’d need a lot more fibres.”

Dr Gross says to meet the growing demand for movement of data, telecommunication companies need technologies that offer greater data flow for reduced cost. The new fibre contains 19 cores that can each carry a signal, a ground-breaking development which could impact many industries.

Dr Simon Gross is an ARC Future Fellow in the School of Engineering and MQ Photonics Research Centre.

Michael Withford is a Distinguished Professor (Core) in the School of Mathematical and Physical Sciences and the MQ Photonics Research Centre.

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