Sound drives next-gen chips
Australian engineers are working on new microchips that use light and sound rather than electricity.
The high-capacity, low-power chips will be important for the development of future tech, according to researchers from the University of Sydney Nano Institute and Max Planck Institute for the Science of Light in Germany.
The information on a chip in acoustic form travels at a velocity five orders of magnitude slower than in the optical domain.
This delay allows for the data to be briefly stored and managed inside the chip for processing, retrieval and further transmission as light waves.
Light is an excellent carrier of information and is useful for taking data over long distances between continents through fibre-optic cables.
But this speed advantage can become a nuisance when information is being processed in computers and telecommunication systems.
In the latest project, the experts have examined ways to remove ‘hot’ electrons from the chips.
“As demand for high bandwidth information systems increase, we want to get ahead of the curve to ensure we can invent devices that don’t overheat, have low energy costs and reduce the emission of greenhouse gases,” said researcher Dr Moritz Merklein.
The idea is to use sound waves, known as phonons, to store and transfer information that chips receive from fibre-optic cables. This allows the chips to operate without needing electrons, which produce heat.
However, information transferred from fibre-optic cables onto chips in the form of sound waves decays in nanoseconds, which is not long enough to do anything useful.
“What we have done is use carefully timed synchronised pulses of light to reinforce the sound waves on-chip,” said Dr Birgit Stiller, who moved from the University of Sydney to lead an independent research group at the Max Planck Institute.
“We have shown for the first time that refreshing these phonons is possible and that information can therefore be stored and processed for a much longer time,” she said.
The scientists carefully timed pulses of light to extend the lifetime of the information stored in sound waves on the chip by 300 per cent, from 10 nanoseconds to 40 nanoseconds.
The research, published in the journal Optica, was done in collaboration with the Laser Physics Centre at the Australian National University and the Centre for Nano Optics at the University of Southern Denmark.
The engineers plan to use this method to extend how long the information remains on-chip.
“Acoustic waves on chips are a promising way to store and transfer information,” Dr Stiller said.
“So far, such storage was fundamentally limited by the lifetime of the sound waves. Refreshing the acoustic waves allows us to overcome this constraint.”