IBM scientists have unveiled their latest step towards replacing electrical signals that communicate via copper wires between computer chips with tiny silicon circuits that communicate using pulses of light.
IBM claims that the device, called a nanophotonic avalanche photodetector, is the fastest of its kind and can receive optical information signals at 40Gbps (billion bits per second) and simultaneously multiply them tenfold.
According to IBM, the new device explores the ‘avalanche effect’ in Germanium, a material currently used in production of microprocessor chips. It operates with a 1.5V voltage supply and the avalanche multiplication takes place within just a few tens of nanometers (one-thousandths of a millimeter).
The company said that its device is made of Silicon and Germanium with standard processes used in chip manufacturing. Thousands of these devices can be built side-by-side with silicon transistors for on-chip optical communications.
In December 2006, IBM scientists demonstrated silicon nanophotonic delay line that was used to buffer over a byte of information encoded in optical pulses. In addition, IBM announced the development of an ultra-compact silicon electro-optic modulator that converts electrical signals into the light pulses, in December 2007.
In March 2008, IBM scientists announced what they say was the world’s tiniest nanophotonic switch for directing traffic in on-chip optical communications, ensuring that optical messages can be efficiently routed.
Chen, vice president of science and technology at IBM Research, said: This invention brings the vision of on-chip optical interconnections much closer to reality. With optical communications embedded into the processor chips, the prospect of building power-efficient computer systems with performance at the Exaflop level might not be a very distant future.
