Laser technique pushes data at 40Tbit/s through existing internet cabling

Researchers have found a way to push more data through existing internet cabling infrastructure reaching speeds of up to 40Tb per second. The speeds, which are fast enough to download around 5,000 standard-definition Netflix films in a second, were achieved by using a new way of splitting up light channels to deliver more information inside and between data centres. Instead of using a single channel, the team use multiple wavelengths to deliver information all on a single Photonic Integrated Circuit (PIC).

PICs use photonics or light-based technology to deliver much higher bandwidth in a power-efficient manner than traditional chips. By using what are known as optical combs, a single laser can be used to generate a broad spectrum of equally-spaced optical frequencies which enable higher capacity internet traffic on a single fibre without upgrading existing infrastructure. It does this by eliminating ‘guard-bands’ or wasted chunks of bandwidth needed in traditional systems that prevent interference between data channels.

Frank Smyth, founder of Dublin-based Pilot Photonics, which is working on the project as part of a pan-European collaboration, said: “A way to visualise how our photonic integrated circuits are helping the flow of information between data centres is to think of road to rail. “On the road, the lanes must be much wider than the cars because the driver can veer left and right to some degree. This extra lane space represents the guard bands between wavelengths that are used in optical systems today.

“With rail, you can pack trains right up side-by-side because they are on fixed tracks and cannot veer off them; this is like using an optical comb. The trains can’t bump into their neighbours because they are on fixed tracks. Data channels based on an optical comb can’t interfere because the spacing between them is physically and fundamentally fixed.

“Rather than growing data rates on a single wavelength, our technology allows us to use multiple wavelengths at a lower speed, thus removing integrity pressure on a single band. These multiple wavelengths create a single channel known as a ‘superchannel’, enabling longer distances to be travelled by the data and making it easier to maintain good signal integrity. “Innovations such as ours solve a real problem for our customers in the industry who need to keep up with society’s insatiable demand for new bandwidth-intensive data services without significant price increases.”

Last week, Openreach and Nokia conducted tests on a new ‘Full Fibre’ technology that can deliver download speeds up to 25 gigabits per second to UK households.

Currently, the fastest speeds available to consumers top out around 1Gbit/s, and even these speeds are only scantily available in the UK. 

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