Who Needs Electrons? Light can carry more information faster than electricity. Now engineers want to use it in computers.

Byline: Michael Hastings

Last Christmas, Dr. Mario Pannicia received a gift not even Santa Claus could deliver. He and his colleagues at Intel's Silicon Photonics Lab succeeded in making the first laser out of silicon, the stuff of ordinary computer chips. "I remember I got the call on Dec. 23," he recalls. "One guy was jumping up and down, he was so excited. You almost don't believe it. You have to convince yourself it's real." He immediately called in outside experts to confirm the finding, and spent the rest of the holiday banging out a paper, which was published a month later in the scientific journal Nature.

Pannicia and his colleagues aren't the only optics researchers celebrating. While optical computing was heralded more than a decade ago as the next quantum leap in information technology, scientists had until recently failed to deliver on that promise. Now, a spate of new discoveries may finally allow engineers to build computers that handle information in the form of light rather than electricity.

Engineers have long appreciated the superiority of light over electricity for carrying reams of information. In the 1970s, telephone companies replaced copper transatlantic transmission cables with ones made of optical fibers, and today the backbone of the Internet is sent through the fibers as pulses of light. The problem has been when those pulses reach their destination: they must be converted to electricity before a computer can use them, slowing the flow of information to a trickle. Scientists have made large computers and servers capable of handling light, but they've had to use exotic semiconductors that were prohibitively expensive.

Many scientists have held that the obvious solution--to make optical chips out of silicon, which is cheap--would never work because silicon isn't very good at conducting light. But a few engineers kept slogging away. One of them was Intel's Pannicia, who figured out how to get silicon to emit laser light. He and his colleagues etched a tiny path in the silicon to conduct light using specially designed mirrors. Initially, the lasers wouldn't work because the chips got clogged with electrons. Pannicia's team found a way to "flush out" the electrons with a vacuum and a strong positive charge, and ended up doubling the laser's strength.

Meanwhile, scientists at IBM's research labs in Yorktown Heights, New York, designed a tiny device that can slow down ...