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Quinn
02-16-2005, 08:35 PM
Better Lasers From Chips, and Likewise

By JOHN MARKOFF

Published: February 17, 2005



SAN FRANCISCO, Feb. 16 - Intel researchers have made an important advance in blending silicon chip technology with optical lasers. The new approach could lead to a significant cost reduction in high-speed communications systems by the end of the decade, as well as new low-cost medical and military applications for lasers, researchers say.

In a report on Wednesday in the magazine Nature, the Intel researchers described the construction of a silicon laser that generates a "Raman effect" that greatly increases the power of a laser.

The Raman effect - in which light is amplified when it passes through a transparent material - is now used to extend the range of lasers used in communication systems based on glass fiber.

The new Intel process miniaturizes the Raman effect so it can be produced within a single silicon chip rather than requiring strands of glass fiber that stretch for miles. The Intel researchers were able to demonstrate that the effect is 10,000 times as strong in silicon as has been achieved in glass fiber.

The advance also means it may be possible to create silicon lasers using Intel's standard chip-making technology. That could sharply reduce the cost of creating optical electronic components like amplifiers, wavelength converters and other types of lasers, which are now made using bulkier mechanical assembly techniques.

"We will be working aggressively to see this into products by the end of the decade," said Mario Paniccia, director of the Photonics Technology Laboratory of Intel. "From a communications technology standpoint, this is very exciting."

Today, most long-distance data and voice communications are transmitted via fiber optic cable systems, while desktop computers and office networks are connected by metal wires. Many in the computer and telecommunications industries say the speed of computers could be increased if the chips within computers were connected by glass fibers rather than by metal wire.

A number of researchers said that Intel's interest in optical communications was largely driven by a need to get around the inherent speed barriers in metal wires that limit the performance of computers.

"It is a very good idea to join photonics" with standard chip-making technology, said David Miller, director of the Solid State and Photonics Laboratory at Stanford University. However, he noted that technical challenges make the manufacturing of pure silicon laser components still a number of years away.

"The silicon laser is a neat science experiment," said Alan Huang, a physicist who pioneered silicon laser research at Bell Labs during the 1980's. "A lot more has to be demonstrated before it can be considered a real device."

The Intel group has made several recent advances in silicon photonics. Last year, it reported the design of a silicon-based modulator, which permits the lasers to be switched on and off, enabling them to carry data.

Intel, based in Santa Clara, Calif., is not alone in doing research in this field. Several California start-up companies are pursuing silicon photonic advances, including the Luxtera Corporation in Carlsbad, Calif., financed by venture capital.

Progress appears to be coming rapidly. Last week, a group of researchers at the University of California, Los Angeles, published a report of a technique for switching a silicon laser directly without the need for a separate modulator. That group, which is financed by the Defense Advanced Research Projects Agency of the Pentagon, is working closely with Intel.


http://www.nytimes.com/2005/02/17/technology/17fintel.html