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Intel has developed a way to move light through silicon at gigahertz speeds that could boost the bandwidth of servers and PCs with photonic connections, the company says.

Huge Speed Boost

In an article published in the current of Nature magazine, Intel details its work on a silicon photonics modulator that uses light to emit steams of data much the way today's chips use electricity. The chipmaker built a modulator that runs at 1GHz, far faster than the previous limit of around 20MHz, says Victor Krutul, Intel's senior manager of silicon photonics strategy.

The modulator essentially acts like a shutter that intermittently blocks a light beam, turning it off and on, Krutul says. The resulting on and off pulses of light correspond to the digital "0s" and "1s" that make up a stream of computer data, he says.

Optical devices are mostly used in large-scale deployments such as underseas cable due to the expense of constructing and maintaining such a link, Krutul says. They can carry far greater amounts of bandwidth than copper wires, and cause less interference, but are extremely expensive for anything but a few specific uses because of the exotic materials required to build the optical equipment, he adds.

Cheaper, Faster Chips

By bringing optical technology into silicon, Intel can reduce the cost per modulator, much the way it has reduced the cost per transistor of its processors, Krutul says. The company can also reduce the size of these optical devices to the point where they can be used in servers, and eventually PCs, he says.

But those days are still off in the future. Intel will have to increase the speed of the modulator to 10GHz before it is practical for server backplanes, Krutul adds. He doubts that will happen before the end of the decade.

When it does happen, optical connections could increase the speed of server connections and decrease the complexity of maintaining a network. Optical connections can take advantage of a technique known as multiplexing, where a number of different optical signals with different wavelengths can be sent down the same cable, Krutul says. This could help greatly reduce the maze of cables pouring out of the back of a conventional server rack, he says.

Intel will discuss the breakthrough in more detail during its Intel Developer Forum next week, where it usually provides attendees with a glimpse of some technologies such as photonic modulators that are seven to ten years away from entering the real world.