Bimetallic all-optical switch could lead to faster computer processors
Researchers at the US Department of Energy’s (DOE) Argonne National Laboratory and Purdue University have created a new kind of all-optical switch that can both transmit data and store it efficiently. The scientists say that their bimetallic switch, which is described in a new paper in Nature Communications, could pave the way for faster computer processors.
Conventional processors seem to have reached the upper boundary of their “clock speeds” — a measurement of how fast they can toggle on and off — due to the limitations of electronic switching. Scientists looking to make improvements in computer processors have therefore become intrigued by the potential of all-optical switching, which uses light instead of electricity to control how data is processed and stored on a chip. The authors of the new paper say that their all-optical switch could realise this potential.
“Previous iterations of optical switches had fixed switching times that were ‘baked in’ to the device upon its fabrication,” said Argonne’s Soham Saha, one of the laboratory’s Maria Goeppert Mayer postdoctoral fellows, who is working in the Argonne Center for Nanoscale Materials, a DOE Office of Science user facility.
Saha and his colleagues have made an optical switch out of two different materials, each with a different switching time. One material, aluminium-doped zinc oxide, has a switching time in the picosecond range, while the other material, plasmonic titanium nitride, has a switching time more than a hundred times slower, in the nanosecond range.
“When you use optical components instead of electronic circuits, there are no resistive-capacitive delays, which means that in theory you could operate these chips a thousand times faster than conventional computer chips,” Saha explained.
The difference in switching times between the two metal components means that the switch can be more flexible and used to both transmit data quickly while also storing it effectively, according to Saha. “The bimetallic nature of the switch means that it can be used for multiple purposes depending on the wavelength of the light that you use,” he added. “When you want slower applications, like memory storage, you switch with one material; for faster applications, you switch with the other one. This capability is new.”
In the experimental configuration, the materials of the switch function as light absorbers or reflectors, depending on the wavelength of operation. When they are switched on by a light beam, they switch state.
Controlling the speed of all-optical switches is crucial for optimising their performance in various applications. These findings offer promise for the development of highly adaptable and efficient switches in fields like enhanced fibre optic communication, optical computing and ultrafast science. The ability to adjust switch speeds also brings us closer to bridging the gap between optical and electronic communications, enabling faster and more efficient data transmission.
Argonne National Laboratory press release: https://www.anl.gov/article/researchers-develop-alloptical-switches-that-could-lead-to-faster-computer-processors
