April 03, 2001, 4:40 PM — As the limitations of miniaturization appear to have been reached for today's electronic computers, researchers are trying to push beyond them by substituting light for electrical voltages in computer components.
"What we are accomplishing in the lab today will result in the development of superfast, superminiaturized, superlightweight and lower-cost optical computing and optical communication devices and systems," says Donald Frazier, a senior scientist for physical chemistry at NASA's George C. Marshall Space Flight Center in Huntsville, Ala., where scientists are working on solving a variety of problems that must be overcome before digital optical computing can be realized.
But will these superfast, supersmall digital optical computers have general applications? Or is that the wrong question to ask?
Just as an earlier era saw superhighways built with more capacity than anyone imagined would be needed - and where traffic now idles for miles in smoggy jam-ups - once digital optical computers are built, applications will follow.
Using light instead of electrical voltages to perform computations and communications, digital optical computers are said to promise switching speeds and parallelism that will swamp the capacity of today's massively parallel computers and could eventually put that kind of computational power on desktops, if not in handheld devices.
They'll be in satellites managing the ever-expanding demands of communications, and they'll be aboard long-term space flights, says physicist Hossin Abdeldayem, also at NASA's Marshall Space Flight Center. The need for the power of optical computing is already being met through programs that do complex modeling, such as those used for weather prediction, he says.
Computations that would take 11 years with conventional electronic computers will take only one hour with optical computers, Abdeldayem adds.
The need for this kind of speed already exists, he says, though it will take another 10 years before computers using all-optical digital technology are on the market. Abdeldayem says he's worried that Japan and Europe are investing more heavily than the U.S. in the research that needs to be done.
The first stage in the movement toward an all-optical world will probably be hybrid electro-optical computers. On-chip miniature lasers and detectors controlled by electronics can already be manufactured. The optics will handle the communications, with light traveling along fibers or films; the advantage over electrical communications is that light waves don't generate cross-talk or require insulation. Frequencies can be multiplexed to easily achieve parallelism.