US Researchers Develop Light-Based CPU

A group of researchers from the University of Colorado Boulder, the University of California, Berkeley, and the Massachusetts Institute of technology have created a CPU that eschews electricity to transfer data in favour of light, which operates at astronomical speeds but uses a fraction of the energy required to run a standard processor. The remarkable photonic chip has been revealed in a new paper published in the academic journal Nature.

“Light based integrated circuits could lead to radical changes in computing and network chip architecture in applications ranging from smartphones to supercomputers to large data centers, something computer architects have already begun work on in anticipation of the arrival of this technology,” Miloš Popović, Assistant Professor at CU-Boulder’s Department of Electrical, Computer, and Energy Engineering and a co-corresponding author of the study, told CU News Center.

Measuring in at 3mm by 6mm, the photonic CPU operates at a bandwidth density of 300 gigabits per second per square millimetre, a rate of up to 50 times higher than that of the conventional electrical-based microprocessors of the current market. The chip uses 850 optical input/output (I/O) components to transmit data at superfast speeds.

“One advantage of light based communication is that multiple parallel data streams encoded on different colors of light can be sent over one and the same medium – in this case, an optical wire waveguide on a chip, or an off-chip optical fiber of the same kind that as those that form the Internet backbone,” he Popović, adding, “Another advantage is that the infrared light that we use – and that also TV remotes use – has a physical wavelength shorter than 1 micron, about one-hundredth of the thickness of a human hair,” said Popović. “This enables very dense packing of light communication ports on a chip, enabling huge total bandwidth.”