Researchers have created a tiny low-energy device – an optical switch that can move the light from one computer chip to another in 20 billionths of a second, faster than any other similar device. The compact switch is the first to redirect light with very low signal loss while operating at voltages low enough to be integrated into low-cost silicon chips.
The low-energy device’s record-breaking performance represents a significant new step toward developing a computer that processes information using light rather than electricity. Using photons, or light particles, to transport data within a computer has several advantages over electronic communications. Photons travel faster than electrons and do not waste energy by heating computer components. Managing waste heat is a significant impediment to improving computer performance. Light signals have been used for decades to transmit information over long distances via optical fibers, but the fibers are too large to carry data across a computer chip.
The new low-energy device switch combines densely packed nanometer-scale gold and silicon optical, electrical, and mechanical components to channel light into and out of a miniature racetrack, change its speed, and change its direction of travel.
The low-energy device has a wide range of applications. The switch in driverless cars could quickly redirect a single light beam that must constantly scan all parts of the roadway to measure the distance to other vehicles and pedestrians. The device may also make it easier to use more powerful light-based circuits in neural networks rather than electricity-based ones.