Cardiff cleanrooms take on the challenge of making light-based AI switches

A switch that routes data as light, rather than as electrical signals, is being pushed closer to production in Cardiff. Finchetto, a technology company, has joined forces with Cardiff University on a ten-month programme meant to work out how the photonic chips behind its switch could be made, as reported by WalesOnline on 14 October 2026.

WalesOnline put the partnership at the top of its round-up of Welsh business deals and described the networking device as a world first. The work is taking place far from Caernarfon and the rest of Gwynedd, in the capital, yet it bears on a question that reaches every part of Wales: how the computing behind artificial intelligence can keep growing without an ever heavier call on electricity.

What Finchetto wants to build

The core of the project is a packet switch. In any network, data is broken into small blocks, and the switch is the piece of equipment that reads where each block is headed and sends it on. Finchetto’s design is described as fully optical, meaning the signal is handled as light from end to end instead of being turned into electricity for routing. The company holds a patent on this approach, and its chief executive and co-founder, Mark Rushworth, has called the technology “fully passive”.

For a switch like this to leave the laboratory, its optical functions have to be built into chips. Under the programme, Finchetto will develop photonic integrated circuits, usually shortened to PICs, made from thin-film lithium niobate, known as TFLN. These circuits are intended to carry the patented switching technology. The stated purpose of the ten months is manufacturing: finding a dependable process by which such circuits can be produced.

The speed and power claims

Measured against conventional electro-optical switches, the technology is said in the report to cut latency, the delay before data reaches its destination, by a factor of 700, and to cut power use by a factor of 20. Those are the only performance figures given. The WalesOnline article did not explain how they were measured, under what conditions, or whether anyone outside the company had checked them, so they are best treated as claims made for the technology.

Why the cleanrooms matter

The setting is part of the story. Funding for the programme allows Finchetto to use the cleanrooms of the university’s Institute for Compound Semiconductors, with the work based in the Sbarc/Spark innovation building.

A cleanroom is a space in which the air is filtered without pause and the number of floating particles is held extremely low. People working inside generally wear full-body suits, gloves and masks and pass through airlocks, because skin flakes, hair and ordinary dust can be far larger than the structures being made. On a chip whose features are microscopic, a single stray speck can spoil a circuit, which is why semiconductor and photonic devices are fabricated in rooms of this kind. Temperature, humidity and vibration are usually kept under control too, so that each production step behaves in the same way every time.

Compound semiconductors are materials built from more than one chemical element. They are widely used in devices that emit, detect or steer light, which makes a facility devoted to them a natural home for photonic chip work.

Why data centres are looking at light

AI systems are trained and run in data centres crowded with processors that exchange information constantly. Much of that traffic already moves along optical fibre, but at many points it is converted into electrical signals so that conventional electronics can process and route it, and then turned back into light. Every conversion uses energy, adds a little delay and gives off heat, and the heat must then be taken away by cooling equipment that draws yet more power.

Photonics, the science of generating, guiding and detecting light, offers a way round part of that cycle: if data can be steered while it stays as light, some of those conversions are no longer needed. That reasoning lies behind the way WalesOnline presented the Cardiff chips. By relying on light in place of electricity to move data, they are meant to ease the electricity and cooling load of AI systems, and the work could lower the power needs of data centres with a large appetite for energy.

Who is funding it

Support comes from two directions. Finchetto secured a grant under the Investor Partnerships Programme, and Development Bank of Wales invested privately and holds an equity stake in the company.

Jack Christopher, a senior investment executive at the bank, said in comments carried by WalesOnline that the country is strong in compound semiconductors and photonics, and that this was the reason for backing the Cardiff work. In his view, locating specialist process engineering in the city would make the region more competitive and add depth to its expanding cluster of photonics innovation.

Mr Rushworth said the programme moves the company’s networking technology towards something that can be manufactured, while drawing on the UK’s existing strengths in making photonic components. He described photonics as a possible route to “radically more efficient” computing for AI and data communications, and argued that the UK would need home-grown capacity in the field to stay competitive. The report framed the company’s involvement in the same terms, as progress towards a UK ability to manufacture photonic technology on its own soil.

A firm with roots in the city

Finchetto is not new to Cardiff. According to the report, it has an established office there and has carried on recruiting locally. It also runs an office and a laboratory in Guildford, Surrey.

What the report leaves open

Several points were not set out in the WalesOnline coverage. It gave no start or end date for the ten-month programme, no timetable for a commercial switch, and no figure for either the grant or the bank’s investment. What it did establish is the shape of the project: a patented optical switch, a university cleanroom suited to chip fabrication, and a Welsh development bank holding a share in the company that hopes to make it.

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