Optics could push chips beyond 10Ghz

Ashlee Vance, IDG News Service\San Francisco Bureau
October 17, 2001, 15:28


SAN JOSE, Calif. - As chip makers battle to increase their processor speeds, they are quickly running into problems controlling the amount of heat generated by swifter processors. One company is looking to solve the temperature issue with a futuristic approach that involves putting fiber-optic technology on a chip, possibly making it easier to transfer information and reduce the heat around a processor.

To increase the performance of processors, companies such as Intel Corp. and Advanced Micro Devices Inc. (AMD) try to double the number of transistors on a chip about every 24 months and push processing components closer together. Both of these techniques tend to increase the amount of heat produced by a processor, to the point that companies are now trying to find new ways to dissipate heat and spread components farther apart.

The temperature issue is likely to come to a head in 2005 as the first 10GHz processors come to market, said Bill Pohlman, chairman and chief technology officer at Primarion Corp., speaking Tuesday at the Microprocessor Forum event held here. Using current technologies, the 10GHz chips would probably create too much heat to make them practical inside of a computer, Pohlman said.

"If you think you can take a 10GHz CPU (central processing unit) and stick it in a box you have today, it is probably not going to happen," Pohlman said.

Instead of using electric current to send information between a processor and, for example, memory, Pohlman proposed that chip makers begin to use higher speed fiber-optic technology attached to a processor and as a connection to other components. Using optical connectors will allow chip makers to spread components farther apart and dissipate much of the heat generated by current processors.

In addition, optical connectors would create more efficient, bigger pipes through which to send information. This could help solve another problem chip makers are facing: I/O technology improvements have also lagged behind increases in processor speeds.

One analyst was impressed with the vision Pohlman presented, saying it could be a practical solution for the chip industry moving forward.

"Right now you have to scrunch things together," said Nathan Brookwood, principal analyst with Insight 64, in Saratoga, California. "If you space out the components, it makes the thermal problems much easier to deal with."

With a processor and memory linked via an optical connector, bandwidth speeds could increase tenfold while those components would require one-tenth as much power, helping solve both power and I/O issues, Brookwood said.

Brookwood agreed that optical connectors could solve both of these problems, because sending information with light instead of electricity has great advantages. Information sent with electrical connectors would only travel about one-tenth as fast as data sent via light over circuit boards, he said. In addition, it requires less energy to send information with optical connectors, and the information signal degrades less with optics.

Using optical connectors is a method attracting interest across the industry, although no one yet has deployed the technology, Brookwood said. Intel Corp. is also working on optical connectors, as the company races to raise chip speeds, Brookwood said.

For optical connectors to become widely used, chip makers and computer makers will have to work even more closely together and plan out their computing systems well in advance, Pohlman warned.

Even if the 10GHz barrier can be surpassed with optical connectors, companies still will need to develop new technology to push processor speed even higher. An Intel executive said earlier this year that current methods of semiconductor design would lead to chips with thermal densities greater than that of a nuclear reactor by 2010.

Primarion, based in Tempe, Arizona, can be reached at http://www.primarion.com/.