Researchers achieve 40Tbps internet speeds with photonics

20 Jul 2021

Image: © alphaspirit /

The multinational team devised a way to vastly increase the performance of existing fibre optic infrastructure.

An EU-funded research team say they have discovered a way to use photonics technology to vastly increase the bandwidth of existing fibre optic cables, achieving internet speeds of up to 40Tb per second.

The project is a collaboration between Pilot Photonics, an Irish optical electronics start-up, and ACTPHAST 4.0, an EU-funded research incubator for companies working in the area of photonics. It includes scientists and engineers from Ireland, Germany and the Netherlands.

According to the study’s authors, “the internet is currently reaching a limit in performance and power efficiency”. The spread of data-heavy services such as FaceTime and Netflix, the proliferation of driverless cars, and the advent of the internet of things will only increase strain on the existing network. Their research therefore focused on ways to increase the throughput of existing infrastructure without having to physically lay new cables.

The basis of the system is Pilot Photonics’ optical comb, a specialised laser that generates a spectrum of equally spaced beams of different frequencies from a single source, like the teeth in a hair comb. Using the optical comb as opposed to multiple independent lasers eliminates the need for guard bands of empty space between data channels, which are usually necessary to prevent interference.

Frank Smyth, co-founder, CTO and former CEO of Pilot Photonics, explained: “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.”

The system also makes use of photonic integrated circuits (PICs). Rather than circuits made of silicon that transmit electrical impulses, PICs are made of indium phosphide and transmit light. Multiple photonic functions including the laser, amplifiers, modulators and receivers can therefore take place on a single chip. It would otherwise be necessary to interface a standard silicon IC with a laser, increasing manufacturing complexity.

“At Pilot Photonics, using a comb laser, we can combine four, eight or 16 transceivers onto a single chip bringing down power consumption, cost and size,” said Smyth.

“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.”

Pilot Photonics was founded in 2011, spinning out patents from Dublin City University and the Tyndall National Institute. It raised almost €1m of funding in 2018.

This week, Japanese researchers set an internet speed record of 319Tbps, also using comb lasers.

Jack Kennedy is a freelance journalist based in Dublin