Computing at the speed of light

Tomorrow’s computers could run at the speed of light – literally

What is it?

Optical computing – sometimes referred to as photonic computing – is an emerging technology that uses beams of visible and UV light energy to process, transfer and store data.

What’s the point of that?

Currently, all computers process data as electronic pulses. In basic terms, data is moved through integrated circuits, semi-conductors and other components as a flow of electrons. But photons (light particles) travel much faster than electrons. Therefore, replacing traditional electronic circuits in PCS and other devices with optical ones could dramatically increase their processing power.

Better still, it’s possible to split a beam of light, meaning optical processors could carry out multiple complex calculations simultaneously, rather than performing each one in sequence, as processors currently do.

Are there other benefits I should know about?

Well, not only would this make our devices faster, it would also probably make them smaller. That’s partly because multiple beams of light can pass through each other without any cross-interference, whereas the electrons that power devices often need to be routed through complex networks of physical wiring. In addition, optically powered PCS would potentially use less energy than traditional computers. So, in theory, the technology could deliver the number-crunching power and speed of a supercomputer in a low-power device the size of a small desktop PC.

The more powerful optical computers would be much more efficient at handling ‘big data’ projects, such as genome analysis and global weather prediction. And optical technology could potentially open the door to further ground-breaking advances, such as quantum computing.

Isn’t optical technology already available?

Yes, but only in a limited capacity. CDS and DVDS use optical technology to read from and write to discs using a laser, for example. And fibre-optic cable is commonly used to deliver fast broadband and cable TV services. But, apart from prototype devices, such as the optical PC built by UK company Optalysys ( www. optalysys.com, see main image), there aren’t any fully optical computer systems just yet.

So, when can I get my hands on a superfast optical PC?

Don’t hold your breath. The technology hasn’t been perfected yet and there are still a number of stumbling blocks to overcome. Not least is the fact that light-based data is actually too fast to control and generates a lot of heat. However, a recent breakthrough made by researchers at the University of Sydney has brought optical computing one step closer. Scientists were able to slow down light-based data to manageable speeds and keep things cool by temporarily converting it into sound waves on a special glass microchip, effectively creating a safe ‘acoustic buffer’. You can read more about their findings in the paper they published last month at Nature.com ( www.snipca.com/25666).

Can’t we just stick with ‘normal’ PCS?

As predicted by Moore’s Law, traditional electronic computer processing power has effectively doubled every two years – at least it has until now. But even Gordon Moore himself (founder of Intel and the brain behind Moore’s Law, pictured) has recognised that the rate of progress is slowing. And this won’t just affect the speed of our home PCS – it could also slow the rate of overall technological advancement, social change, productivity, industrial development and economic growth, all of which are largely driven by digital progress. A radical new microchip te technology, such as optical pr processing, could help to reverse th that slowdown.