Electronic interconnect beats wire speed

Engineers at Johns Hopkins University's Department of Electrical and Computer Engineering are developing a new way of manufacturing microchips. Unlike the microchips in most computers that use thin slices of silicon as the semiconducting material, the new chip design uses layers of silicon on slices of synthetic sapphire. The sapphire is an insulator. And it allows light to pass through it. Andreas G. Andreou is a professor at the lab where the research is done. "We've developed a very fast way of getting data on and off a chip without using wire," says Andreou. His team uses light beams in place of metal wire. Electrical signals are transformed into light pulses and then beamed through the transparent sapphire substrate via a laser. At its destination, the light enters the high-speed optical receiver circuit that transforms the stream of photons into a stream of electrons that continue their journey through wiring connected to other computer components. Using optical signals, Andreou believes that a signal could move 100 times faster than it does along a metal wire. The opto-electric interface also requires less power because the substrate is an insulating material, not a semiconducting material. Thus, it reduces the power dissipation that commonly occurs in microprocessors when signals travel through wires that have capacitance. "Without peristaltic capacitance, it's much faster to send signals at the speed of light," says Andreou. For more information, go to http://www.jhu.edu.