Bytes at the speed of light

Microprocessors are now so powerful that computer circuitry can’t keep up. But thanks to research at York, that may be about to change.

laser speckle

Optical interconnects could hold the key to greater computing speeds.

Anyone buying a laptop in the past ten years may have noticed something: microprocessor performance isn’t making the huge advances in ‘clock speed’ that it used to.

In fact, there’s been very little increase microprocessor core speeds in the last decade, and the reason is straightforward; despite huge advances in silicon technology over the years, electrical circuits carrying information around a computer system simply can’t keep up. If the core processors were to keep increasing their speed, the circuits would melt.


The answer could be “optical interconnects” - a technology which guides light in silicon to carry the information around a computer system. This type of interconnection is already carrying most of our internet traffic and now major computer manufacturers are seeing it as the future of faster computing.

But there’s a problem - silicon doesn’t emit light very well so where will this light come from? Current technology uses lasers mounted onto silicon circuits but there is no fully integrated solution available yet.

Thomas Krauss, Professor of Photonics in our Department of Physics, is part of a team of researchers working to create a device which will solve this problem and potentially restart the speed race, while opening up new applications and commercial opportunities.


He believes optical interconnects could hold the key to greater computing speeds. “The reason these optical connections, or silicon photonics, are so well suited to data communications is because of their excellent compatibility with the existing circuitry, which uses metal-oxide-semiconductor (CMOS) technology,” he says. “But despite making progress with many essential computer components, integrating laser sources with silicon remains challenging.”

So given silicon’s poor light emitting capabilities, the team set about looking at other materials which could give laser-like performance, while remaining ‘CMOS-compatible’. And their findings have now been published.

Professor Krauss says: “We’ve demonstrated a light emitter on silicon using one of the new classes of graphene-like 2D materials to provide the optical gain. The particular significance is that it’s the first time this has been done in the crucial fiber-optic communications band - known as the ‘O-band’ - and it’s this step-change which is so exciting. It opens up this device to a range of real applications and commercial opportunities.”


Dr Yue Wang from our Department of Physics also worked on the project. She explains why the findings have such potential: “The ability to use this material opens new opportunities for deploying current manufacturing methods, and thereby brings ‘2D-on-silicon’ devices a step closer to becoming a scalable technology”.

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"We’ve demonstrated a light emitter on silicon using one of the new classes of graphene-like 2D materials to provide the optical gain.

Professor Thomas Krauss

Professor Thomas Krauss of the University of York initiated this research project, which was carried out in collaboration with Professor Juntao Li at the State Key Laboratory of Optoelectronic Materials and Technologies, Sun Yat-Sen University, China.

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Professor Thomas F Krauss

Professor Thomas F Krauss

Professor of Photonics

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