more on Intel Says Chip Speed Breakthrough Will Alter Cyberworld

[Dave Farber <dave () farber net>]

Delivered-To: dfarber+ () ux13 sp cs cmu edu
Date: Wed, 11 Feb 2004 13:49:57 -0800
From: Ari Ollikainen <Ari () OLTECO com>
Subject: Re: [IP] Intel Says Chip Speed Breakthrough Will Alter Cyberworld
To: dave () farber net

At 3:25 PM -0500 2/11/04, Dave Farber wrote:
>Intel Says Chip Speed Breakthrough Will Alter Cyberworld
>
>February 11, 2004
> By JOHN MARKOFF

        With all due respect to John Markoff...his article makes it
        sound like Intel suddenly discovered digital transmission over
        fiber, when they've actually managed to develop the fastest yet
        (1GHz) silicon modulator. Here's a better article on this
        "breakthrough ":

Intel chip aims to cut optical costs
By Michael Kanellos
CNET News.com
February 11, 2004, 10:34 AM PT
URL: http://zdnet.com.com/2100-1103-5157289.html

Intel has produced a prototype chip that could take a lot of the
manual labor out of manufacturing optical equipment toward the end of
the decade.

The chip, called a 1GHz silicon modulator, essentially takes filtered
laser light and chops it into a data stream of ones and zeros that
then travels down a fiber-optic cable. Because the chip made of
silicon it is potentially cheap to manufacture. But it can
theoretically provide performance equal to existing modulator
technology that's made of more exotic materials, said Victor Krutul,
senior manager of silicon photonics strategy at Intel.

A paper that describes the results will appear in Nature magazine on
Thursday, and Intel plans to further discuss it at its developer
forum in San Francisco next week.

"The ability to process light on the silicon itself could prove to be
very valuable," said Martin Reynolds, an analyst at Gartner.

To date, silicon modulators have topped out at a fairly slow 20MHz,
Krutul said. At the other end of the spectrum, optical communications
manufacturers now produce modulators that operate at 10GHz. But they
are made of expensive materials, such as gallium arsenide.

Current modulators also require "active alignment," which means that
a technician looking through a microscope has to manually attach an
optical fiber to the modulator. In Intel's prototype chip, the
modulator contains a trench--put in the fiber optics, and alignment
occurs automatically.

"Fifty to 60 percent of the cost (of optical equipment) goes into
alignment," Krutul said.

Later in the year, Intel plans to show how its chip can hit the 10GHz level.

Still, the company's chips won't likely hit the market until near the
end of the decade, Krutul said.

Although Intel is typically not associated with optical technology,
the company has set its sights on becoming a major participant in the
market. It has acquired a number of companies in the field, including
laser specialist New Focus, and has engaged in independent research
projects on photonics, the science of marrying silicon manufacturing
to optical technology.

Cost is a large part of the motivation to move to silicon, but it
will likely bring ancillary performance benefits for computer makers.
The electricity that runs through chips creates tremendous amounts of
heat, which, in turn, could crimp performance improvements. Photons,
which carry data in optical fiber, do not.

Optical fiber also has the ability to transfer up to 100 terabits of
data per second, Krutul said, far more than wires.

According to Gartner's Reynolds: "Electrons are quite slow. They move
at a fast walking pace."

As a result of these features, Intel and companies like Primarion are
trying to figure out ways to use optical fiber to connect different
boards or chips inside computer.

Electron storm
Silicon modulators work, because electrons can change the character
of light, a phenomenon known as the plasma effect. In these devices,
a laser beam is split into two waveguides, channels the light travels
down. The two streams of light then pass through two separate phase
shifters, which are used to bombard the light with electrons.

If the phase shifters aren't turned on, the light beams rejoin, and
light goes down the fiber ("1," in data terms). If the phase shifters
emit electrons, the two light beams cancel each other out when they
rejoin, and no light is emitted. That registers as a "0."

"With electrons, you can influence light," Krutul said.

Today's 20MHz silicon modulators use a technique called current
injection. To get to 1GHz with this method, the waveguides would have
to be 1/100th of a micron wide. Intel's 1GHz modulator comes with
waveguides that can measure about 1.5 microns. (A micron is a
millionth of a meter.)

Professor Graham Reed, an expert on silicon photonics at the
University of Surrey, said current injection silicon modulators will
likely be able to accomodate wider waveguides. However, no one has
yet done it.

"They reorganize the charge in the device rather than injecting it,
so it's quicker," he wrote in an e-mail. "It's also a device that has
some similarities with a transistor, so (Intel) can make them well,
too, so it's a big deal, because they've got it to work
experimentally."

Much of the initial research regarding the plasma optical effect came
out in the mid-1990s, when Intel and other manufacturers began to
plant chips upside down on motherboards. Because the connectors faced
down, manufacturers had no way to directly test if the transistors
inside a chip worked.

A researcher noted that silicon is transparent at infrared
frequencies. By beaming infrared light on a chip region and then
studying the properties of the reflected beam, testers could
determine whether electrons were traveling through certain chip
regions, Krutul said. Intel eventually licensed this technique to
equipment manufacturers.


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       OLTECO                    Ari Ollikainen
       P.O. BOX 20088            Networking Architecture & Technology
       Stanford, CA              Ari () OLTECO com
       94309-0088                415.517.3519 

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