[Laser] Intel says: hundreds of lasers on a doped silicon chip

[Ed]

Intel Claims a Breakthrough In Creating Lasers on Chips

Move to Silicon Platform
May Slash Network Costs;
More-Agile Photonics Gear
By Don Clark - The Wall Street Journal
September 18, 2006; Page B5

Researchers at Intel Corp. and the University of California, Santa Barbara,
are claiming a breakthrough in creating lasers on computer chips, a
development that could lead to sharp reductions in the cost of ultrafast
data communications.

Lasers are important elements in modern communications hardware, sending
data in pulses of light that flow over strands of glass fiber. But
fiber-optic networks are expensive compared with copper wiring and have
tended to be limited to long-distance, high-volume applications.

So scientists have been racing to use silicon, the inexpensive material used
in standard computer chips. Up to now, they have mainly succeeded in
creating the parts of lasers that guide and amplify light beams. They have
had to rely on external components to generate light, because silicon
doesn't emit light efficiently.


Intel hopes to place dozens or even hundreds of lasers on chips like this.
The Intel and UCSB researchers added the missing light-generating capability
by finding a way to glue a layer of indium phosphide, a material used in
conventional lasers, to a silicon wafer. The added material allowed them to
fabricate tiny devices that generate light when electrical voltage is
applied.

"This hybrid approach addresses the last major hurdle," said Mario Paniccia,
director of Intel's photonics technology lab. "We now have all the building
blocks."

Commercializing the technology could take at least five years, Mr. Paniccia
estimated. For one thing, the company's initial test lasers stopped working
at temperatures above about 100 degrees Fahrenheit. The researchers believe
they have identified ways to reduce the sensitivity to heat, said John
Bowers, a professor of electrical and computer engineering at UC Santa
Barbara involved in the effort.

Ultimately, dozens or hundreds of lasers could be integrated onto a single
chip, Intel says. Where comparable lasers now cost from $50 to hundreds of
dollars each, the research team thinks prices as low as a dollar per laser
are achievable, a change that could transform the field known as photonics.

"Intel has helped to debunk the myth that silicon is not good for
photonics," said Alan Willner, a laser expert who is a professor of
electrical engineering at the University of Southern California.

Intel, of Santa Clara, Calif., is initially targeting communications between
components inside computers and within computers in data centers. The
speediest such connections now send about eight gigabits to 10 gigabits of
data per second over distances of as much as 18 inches, Mr. Paniccia said.

With the new technology, speeds of 20 gigabits to 40 gigabits could become
commonplace, over distances of tens of feet, Mr. Paniccia said. As a result,
computer performance could increase sharply and hardware designs could
change significantly; memory chips, for example, would no longer have to be
kept close to microprocessor chips to reduce delays in fetching data, Mr.
Paniccia said.

The move to silicon is "really important," added Stan Lumish, chief
technology officer of JDS Uniphase Corp., a big maker of communications
lasers and related components.

Lower prices for lasers could allow providers of data services to deploy
networks that are more powerful and "agile" -- able to respond flexibly as
needed for communications capacity shifts among different geographic
locations. The trend "will just continue to drive the usage of bandwidth,"
he said.

Write to Don Clark at don.clark at wsj.com