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Light Speed

Optical Computers Promise Amazing Power

By Sascha Segan

March 2 - The power of light may make your computer a hundred million times faster.

Beyond the copper, electricity and silicon that make up the bulk of today's computers, NASA scientists are looking into super fast optical computers, which would replace electrons zooming through metal with light waves refracting through man-made, organic molecules. Though the technology may not become reality for another 15 years, scientists said, the power of optical computers will make today's machines look as slow as abacuses.

"Optically, we can solve a problem in one hour which would take an electronic computer 11 years to solve," said Hossin Abduldayem, a senior research scientist at NASA's Marshall Space Flight Center in Huntsville, Ala.

Seeing the Light

Optics - the science of light - is already used in computing, most often in the fiber-optic glass cables that currently transmit data down Internet lines much more quickly than traditional copper wires.

Unlike a copper cable, which sends electricity one pulse at a time, optical fibers can transmit several pieces of data as waves of different colors of light which can travel down a fiber simultaneously. That's much faster.

"When you send information electronically it has to be done sequentially, whereas with this you can do parallel processing," said Don Frazier, chief scientist for physical chemistry at MSFC. "There's no limitation on how many beams or packets of information you can send at once."

As electronic chips get denser and denser, and the tiny switches that let computers make decisions get smaller and smaller, eventually they're going to reach a physical limit where circuits can't get any smaller, Frazier said.

That's where optical computers come in. Using light moving through and refracted by thin films of man-made organic molecules rather than electrons streaming through metal, they would move and process data much faster. Just like the difference between fiber-optic cables and copper wire, optical computers will be able to do parallel computations where electronic machines have sets of lines that move electrons one at a time, Frazier said.

A group of researchers from the University of Southern California has already developed an organic molecule which could theoretically function as a switch three times as fast as the industry standard, Abduldayem wrote in an academic paper, "Recent Advances in Photonic Devices for Optical Computing."

But Abduldayem and Frazier admit that optical computers are at least a decade away. Today's materials require much too much power to work in consumer products, they said. Coming up with the right materials may take five years or more, and it may be a decade after that before optical computing products appear.

Dim View of Optics?

NASA may be riding the all-optical wave with a long-term vision, but some other scientists say the nearer future isn't glowing for machines that run on light. Most shorter-term research is focused on advances in electronics which are promising vastly improved computers with a mix of optical and electronic components, they said.

"All-optical computing has sort of gone out of vogue," said Eric van Stryland, interim director of the school of optics at the University of Central Florida. "Electronics has gotten very good at doing computing, but optics is very good at transmitting information. Computers will be opto-electronic computers," he said.

Optical connections within electronic computer systems will speed data between the parts of a computer, he said, and optical switches will mix in with electronic processors to move information quickly without generating the heat that comes off copper wires.

Optical switches, gates, and "nano-optics" - a combination of optical technology and very, very tiny electronic parts - will help speed computers of the future, said Daniel Blumenthal, a professor of electrical and computer engineering at the University of California, Santa Barbara. In a January Scientific American article, Blumenthal described optical networking technologies that can move data at 160 gigabits per second. That's 16,000 times faster than today's average Ethernet connection.

All-optical technologies may still come to pass further in the future, he said. And even beyond that are "quantum computers," which use the properties of quantum mechanics to process data at incredibly high speeds. (See related story, right.) You'll probably see those on your desk between 2030 and 2050, Abduldayem said.

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-- Tidbit (of@the.day), March 05, 2001

Answers

At this point, I am more concerned about data rate than computing speed. I look forward to a time when clicking on a link will take me immediately to that link.

-- Lars (larsguy@yahoo.com), March 05, 2001.