Sapphire when ready for laser chips

Laser chips made from silicon and sapphire could speed up computing a hundredfold, claim scientists
Written by Rupert Goodwins, Contributor

A tiny chip made from silicon and sapphire and including banks of microscopic lasers may be the future of fast computing, say researchers from Johns Hopkins University in Maryland. By combining optical and electrical techniques, they claim that chips made this way can communicate between themselves up to a hundred times faster than those using purely electrical methods.

"We've developed a very fast and cost-effective way of getting data on and off a chip without using wire," Andreas G. Andreou, professor and director of the lab where the work was done, said in a statement. "It really promises to revolutionize how computer systems for homes and businesses are put together."

Laser light, long used by humans for telephone and data networks, has many advantages over electricity when signalling. It's much less affected by distance, it neither causes nor suffers from interference, and it can work at much lower powers. Until now, these advantages were difficult to realise in packages as small as individual chips.

The researchers have adapted an existing technology called silicon-on-sapphire, where a layer of sapphire is used as an insulator to reduce power demands and speed up circuits built in spirits. However, because sapphire is also optically transparent, lasers built into the silicon can fire through the substrate and send signals to the outside world. Optical receivers can also be built into the silicon, while lenses can be etched into the sapphire to form the laser beams and collect received light. The same system can be used within a chip to move signals around.

Chips made in this way would replace some of the hundreds of pins around their edge with an optical interface area, either coupled to optical fibres or just aligned with adjacent chips for transmission across free air. Construction techniques are not significantly different from standard chips.

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To find out more about the computers and hardware that these chips are being used in, see ZDNet UK's Hardware News Section.

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