A miniature beamsplitter created by American researchers could be the first step towards silicon photonic chips needed for next generation super-fast computers using light instead of electrons.
The device, described in the latest issue of the Nature Photonics journal, is about fifty times thinner than a human hair and forty times smaller than previously existing beamsplitters.
"Light is the fastest thing you can use to transmit information," said Rajesh Menon, associate professor of electrical and computer engineering at the University of Utah and the leader of the team behind the invention.
"But that information has to be converted to electrons when it comes into your laptop. In that conversion, you're slowing things down. The vision is to do everything in light."
Photons are already used to carry information over the Internet through fibre-optic networks. But once a data stream reaches a home or office destination, the photons of light must be converted to electrons before a router or computer can handle the information. Researchers envision that in the future this transition would not be necessary.
"With all light, computing can eventually be millions of times faster," said Menon.
The new beamsplitter has been integrated into a silicon chip, where it divides oncoming light waves into two separate channels of information. A future photonic chip would be equipped with millions of such devices directing light waves in different ways.
Only 2.4 by 2.4 microns in size, the device is ‘close to the limit of what is physically possible’, the researchers said. The smaller the device, the more the researchers could cram them onto a single chip.
The invention of the Utah team uses established fabrication techniques – a major advantage that would allow keeping costs down.
In theory, a smartphone or a tablet running on photonic chips would not only be considerably faster, but also consume less power and thus provide a longer battery life. It would also generate less heat than existing mobile devices.
The first supercomputers using silicon photonics are already being developed by companies such as Intel and IBM. However, these machines use hybrid processors that remain partly electronic.
Menon believes his beamsplitter could be used in such computers in as little as three years.
The technology could also help speed up connections between computers in data centres and provide sufficient speed for future computers responsible for autonomous cars or drones.