Intel demonstrates silicon laser

Intel has devised a laser out of silicon, the latest in a series of steps that could take the expense and pain out of optical communication.

The chipmaker has created a chip containing eight continuous Raman lasers by using fairly standard silicon processes rather than the somewhat expensive materials and processes required for making lasers today. The lasers emit a continuous stream of light that can then be modulated into a stream of impulses that can represent data. Cheap optical parts could not only lead to faster computers but also to less expensive and more accurate medical equipment.

While silicon lasers are not likely to enter the market for at least four to five years, the chip should generate enthusiasm and interest in the industry. Although manufacturers love silicon, it's typically a terrible carrier for optical data.

"This is a scientific breakthrough, and a psychological breakthrough, because no one thought you could do it," said Mario Paniccia, director of the photonics technology lab at Intel. Silicon is not a good optical material in ordinary circumstances, he added.

The laser represents the latest step in Intel's plans to adopt optical links to connect computers, chips or eventually even subcomponents on the same chip. Last year, the company showed off a silicon modulator that is on its way to running as fast as the exotic modulators of today.

"What Intel is talking about is taking a $2,000 modulator and putting it on a piece of silicon and taking all of the parts you need and putting it into a single package," said Martin Reynolds, an analyst at Gartner. "Clearly, there is a market for it."

It is also part of a larger effort at Intel to employ its factories to make silicon chips that can test blood or perform mechanical tasks rather than just calculate ones and zeros.

Carrying data on light comes with tremendous advantages. Power consumption and heat dissipation have become a huge problem for chip designers. Photons generate far less heat than electrons do when used to carry data. Fibre strands can also handle far more data traffic, thereby cutting down on cabling and the internal volume of computers.

The catch? Optical components are expensive to manufacture and require exotic materials. Assembling the components into complete systems also remains an arduous task.

That Raman lasers could reduce the hassle and expense is a "significant breakthrough", said Jalali Bahram, a professor at the University of California at Los Angeles. Bahram invented the first silicon Raman laser. (Intel's is the first with a continuous beam.)

Current optical equipment requires that the optical fibre serving as the light source be carefully aligned with the laser, said Victor Krutul, senior manager of silicon photonics strategy at Intel. Two-thirds of the cost of finished optical equipment goes into testing and assembling it, he said.

Mass-produced silicon can ameliorate many of these problems. Silicon allows for passive alignment: A groove can be cut into a chip containing a silicon laser. The fiber can then be slotted in quickly, cheaply and accurately.