Project Seeks to Replace Copper Wires With Lasers and Tiny Silicon Circuits; Intel and Universities Have Similar Efforts
By PAUL GLADER And DON CLARK
Researchers at International Business Machines Corp. are claiming an important advance that could change the way computer chips communicate, sharply boosting speed while lowering energy consumption. The goal is to use pulses of light rather than copper wires to exchange information between chips—and to build the needed components out of silicon rather than costly, esoteric materials.
IBM's advance involves a key component called an avalanche photodetector, which converts light into electricity. The researchers say they used silicon and the element germanium to create a photodetector that is among the fastest and least power-hungry of its kind. They are publishing their findings in the scientific journal Nature. IBM isn't alone in the pursuit. Researchers at universities and companies including Intel Corp. and start-up Luxtera Inc., have also been working on improving chip performance using silicon-based optical components.
"This is the next wave of computing," said Richard Doherty, an analyst at market-research firm Envisioneering Group and a patent holder in optical communications. "By 2020, it may be the dominant way Google, governments, banks and other large users are doing their computing." Optical communications involve encoding information on streams of light particles generated by lasers. The technology uses thin glass fibers rather than bulky cables, yet creates connections that allow more data to flow at higher speed.
Such benefits are the reason long-distance phone wires were replaced with fiber-optic cables, a technology developed in the 1970s. Companies like Luxtera already sell silicon-based optical devices for linking up computers. Researchers are racing to miniaturize optical components so they can be built into microprocessors.
Intel has built a series of optical components from silicon and related materials, including a prototype avalanche photodetector it announced in December 2008. IBM says its version can detect 40 gigabits of data a second—four times the speed of Intel's—and operates at 1.5 volts rather than 30 volts. "That can save a huge amount of power," said Yurii Vlasov, the lead scientist on the IBM research. He said IBM's photodetector can detect weak pulses and amplify them without adding unwanted noise, a previous problem with the technology.
Mario Paniccia, director of Intel's photonics technology lab, called IBM's advance another sign of progress in the field. "As a scientist, I think this is all great," he said. "It just drives more competition."
Mr. Vlasov said it could be five years until the technology makes its way into chips for high-end server systems. It could take another five years before it is used in consumer products such as cellphones, he said.
* MARCH 4, 2010
IBM: IBM scientists Fengnian Xia, Yurii Vlasov and Solomon Assefa were part of the team behind the research.
As impressive as the chip is, I love this picture: a Chinese, a Russian, and an Ethiopian; that the US at its best.