You won’t see it livestreamed, but physicists are locked in an intense competition to push ever greater amounts of data down fibre-optic cables – and a newly demonstrated technology promises to help network operators leapfrog surging global demand for data.

Developed by researchers at the UK’s Aston University Institute of Photonic Technologies (AIPT), Japan’s National Institute of Information and Communications Technology (NICT) and the USA’s Bell Labs, the new technology can push data across a single optical fibre core – a single strand of fibre-optic material thinner than a human hair – at speeds of 301 terabits per second (Tbps).

That’s 15 times faster than NBN Co’s 60,000km fibre optic backbone – a bundle of cores that carries NBN traffic around Australia at 19.2Tbps – and 3 million times faster than a 100Mbps consumer National Broadband Network (NBN) connection.

And while it’s far from a world record – that title has hot-potatoed from a University College London team that reached 178Tbps in 2020, to a Swedish and Danish team that moved 1.8 petabits per second (Pbps) over a special cable in late 2022, to a Macquarie University-backed NICT collaboration that transmitted 1.7Pbps over industry-standard cable, to NICT’s surge last year to 10.66Pbps and then 22.9 Pbps – the new technology is significant for a different reason.

To understand why, consider that light waves carrying data bounce along the inside of fibre-optic cores in regular waves, which are described based on their wavelength – the distance from one wave peak to the next.

The colours our eyes can see use wavelengths of between 380 nanometres (nm) and 700nm, while fibre-optic data is transmitted using ultraviolet wavelengths between 1,260nm and 1,675nm that are grouped into six bands named O, E, S, C, L, and U – each with its own performance characteristics based on how the wavelengths interact with the fibre-optic material.

Because C-band wavelengths have the ideal combination of characteristics – low absorption of ultraviolet light and relatively low scattering of the light – most fibre-optic networks have so far favoured data transmission in that band, boosting capacity with a technique called wavelength division multiplexing (WDM) that staggers many wavelengths along the same fibre-optic core; think of dozens of surfers riding the same wave at the same time.

As demand for data surges, scientists have turned to other bands to boost capacity over existing cables rather than spending billions to install more and more of them under oceans and across continents – where costs are estimated at around $40,000 per kilometre.

Last year’s 22.9Pbps NIST speed record, for example, used specialised equipment to push data across 750 channels – 293 S-Band and 457 C-Band and L-Band – simultaneously.

Smashing through the water barrier

The race to squeeze more data down fibre-optic cables has become critical as Internet traffic spirals on the back of new technologies like cloud gaming, digital twins, virtual reality and augmented reality, automation, and artificial intelligence.

Even though a recent Deloitte analysis suggested that individual users’ broadband requirements may be plateauing, overall demand continues to surge: Nokia’s recent Global Network Traffic 2030 report, for one, projected demand for data traffic will increase at 22 per cent to 25 per cent per year through the end of this decade, reaching 3109 exabytes (3.1 billion terabytes) per month in 2030.

The E-Band – which offers three times as much capacity as the C-band – promises room for expansion but has so far been off limits because it includes the so-called ‘water peak’, meaning that light pulses transmitted at those wavelengths are blocked by water molecules trapped in fibre-optic cable during its manufacture.

That’s why the AIPT led team spent years figuring out how to compensate for the challenges of the E-band, ultimately developing new optical amplifiers and optical gain equalisers that dodge the water peak to transmit data down fibre-optic cables using E-band wavelengths.

In the past “no one had been able to properly emulate the E-band channels in a controlled way,” AIPT lead researcher Dr Ian Phillips explained, noting that “growing system capacity by using more of the available spectrum can help to keep the cost of providing this bandwidth down.”

“It is also a ‘greener solution’ than deploying more, newer fibres and cables,” added collaborator Professor Wladek Forysiak, “since it makes greater use of the existing deployed fibre network, increasing its capacity to carry data and prolonging its useful life and commercial value.

“By increasing transmission capacity in the backbone network, our experiment could lead to vastly improved connections for end users.”