Linking with Light Having proven their worth in long-distance
communications, photons will soon take over inside the computer
The movement of data in a computer is almost the converse of the
movement of traffic in a city. Downtown, in the congested core
of the microprocessor, the bits fly at an extraordinary rate.
But further out, on the broad avenues of copper that link one
processor to another and one circuit board to the next, things
slow down to a comparative crawl. A Pentium 4 introduced this
spring operates at 2.4 GHz, but the data travels on a bus
operating at only 400 MHz. The speed picks up again, though, out
on the highways of the world's optical-fiber telecommunications
networks. Obviously, the closer engineers can bring the optical
superhighway to the microprocessor, the fewer copper bottlenecks
can occur, as if you could pull out of your driveway straight
onto the Autobahn. So some researchers say that, within just a
few years, many of the copper connections in computers will
yield to high-speed