Vol. 19, No. 23

March 9, 2000

Researcher pursues faster computers

Imagine computers operating at the speed of light. Geneticists could calculate the formation of DNA in hours or days rather than the 1,000 years it’s predicted to take with current technology, Dennis W. Prather, electrical and computer engineering, said. Prather has been awarded a $500,000 grant from the Department of Defense to buy an instrument that will bring computers one step closer to achieving these speeds. The instrument, called an electronic beam (ebeam) pattern generator, will allow the fabrication of tiny optical elements that can be integrated into a computer’s central processing unit (CPU), enabling it to use light to communicate. Prather explained that as CPUs continue to increase in speed, it becomes more difficult for the key components within the processor to transmit information to one another. Having optical elements take the place of wires that now connect the CPU’s components would allow communication at the speed of light. That would mean that a processor could operate at gigahertz (billions of hertz per second) and in some cases, terahertz (trillions of hertz per second). Today, the average personal computer operates at approximately 500 megahertz or one million hertz per second With this award, Prather has received research grants or awards of more than $3 million from the Department of Defense, National Science Foundation, Sun Microsystems and Gore Inc. Working in the Applied Optic and Electromagnetics Laboratory at UD that Prather founded, he and his graduate students have focused on developing three-dimensional computer architectures that use microscopic optical elements, one-fifth the diameter of a human hair, to control and redirect light on the same scale as a CPU. They’ve created a network of tiny laser beams interconnecting the components of a computer’s CPU. Because optical beams don’t experience the same interference that wires do, there’s nothing to slow down the transmission of digital signals, allowing the computer to process information at phenomenal speeds. “The problem is that optical elements react differently with light when they become very small,” Prather said, so, he developed a new theoretical framework that predicts how these elements will react and how that reaction can be manipulated to create precise laser beam control that can be used as interconnects between CPU circuits. The theory behind the research began with Prather’s dissertation. In the two and a half years he has been at UD, those theories have evolved to the point of fabricating a prototype of the “optichip” for the next generation of computers. With the purchase of the ebeam generator, Prather and his research team will be able to make a prototype that demonstrates the feasibility of the “optichip” for the next generation of computers. “We’re on the brink of blowing this area wide open,” Prather said. One of the research team’s most pressing needs was to have a fabricating machine on site so that the optical elements they’ve designed can be made with more precision. “The machine will allow us to perfect the experimental aspects of our work,” he said, “then, the key will be integrating these parts into a complete system.” The optical elements created by the ebeam machine will have to fit into state-of-the-art silicon chips in order to be practical. Ultimately, Prather said, this process would be used to interconnect the elements of a silicon chip that contains many CPUs forming something like an optical local area network the size of a computer chip. It should take at least a year and a half to know whether his contribution to the new computer architecture will reach fruition, he said. Prather received his Ph.D. in electrical engineering from the University of Maryland in 1997 and joined the UD faculty the same year. Since then, he has established the Applied Optic and Electromagnetics Laboratory where he and his students carry out their research. In 1999, Prather received the National Science Foundation Career Award and the Office of Naval Research Young Investigator Award and became an editor for Applied Optics. –Barbara Garrison