Step Towards Next-generation Computers Using Light


In an attempt to come up with next-generation computers, scientists from the University of Sydney have stored light-based information as sound waves on computer chips and have compared it with capturing lightning as thunder. While this procedure is pretty critical, light-based computers have immense potential compared to the existing electronic computers as they can run twenty times faster without producing too much heat and sucking up energy like the existing devices.

When data is sent through an optical fibre, the information is coded into photons.But finding a way for a computer chip to retrieve and process information stored in photons is a tedious task. It is too fast for the microchips to read.Hence, light-based information that flies across internet cables is currently converted into slow electrons.Researchers from the University of Sydney figured out an alternative of converting this optical information coherently to an acoustic hypersound wave.

Optical information is extracted using the reverse process. The hypersound phonons have similar wavelengths as the optical photons but their velocity is five times lower in magnitude.They used stimulated Brillouin scattering(SBS) to coherently couple two optical waves and an acoustic wave.


As a storage medium, they used a small footprint spiral waveguide made from the chalcogenide glass comprising a rib waveguide structure. While unimpeded light passes through the chip in 2 to 3 nanoseconds, once stored as a sound wave, information can remain on the chip for up to 10 nanoseconds, long enough for it to be retrieved and processed.

Converting the light into sound waves will not only slow it down but also make data retrieval more accurate.”Building an acoustic buffer inside a chip improves our ability to control information by several orders of magnitude,” said Moritz Merklein, one of the researchers.

“Our system is not limited to a narrow bandwidth. So unlike previous systems, this allows us to store and retrieve information at multiple wavelengths simultaneously, vastly increasing the efficiency of the device,” added Birgit Stiller, project supervisor, as stated in their paper published in Nature Communications.