Engineers take a further step toward super-fast computers
18 May 2015
Engineers are closer to creating the next generation of computers and mobile devices capable of speeds millions of times faster than current machines.
University of Utah engineers have developed an ultracompact beamsplitter — believed to be the smallest on record — for dividing light waves into two separate channels of information. The device brings researchers closer to producing silicon photonic chips that compute and shuttle data with light instead of electrons
“Light is the fastest thing you can use to transmit information,” says electrical and computer engineering associate professor Rajesh Menon. “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. With all light, computing can eventually be millions of times faster.”
The Utah team created a much smaller form of a polarization beamsplitter on top of a silicon chip that can split guided incoming light into its two components. Beamsplitters of this kind are relatively large (more than 100 by 100 microns). Thanks to a new algorithm for designing the splitter, Menon’s team has shrunk it to 2.4 by 2.4 microns - close to physical limits.
The beamsplitter would be just one of a multitude of passive devices placed on a silicon chip to direct light waves in different ways. By shrinking them down in size, researchers will be able to cram millions of these devices on a single chip.
Potential advantages go beyond processing speed. The Utah team’s design would be cheap to produce because it uses existing fabrication techniques for creating silicon chips. And because photonic chips shuttle photons instead of electrons, mobile devices such as smartphones or tablets built with this technology would consume less power, have longer battery life and generate less heat than existing devices.
The first supercomputers using silicon photonics — already under development at companies such as Intel and IBM — will use hybrid processors that remain partly electronic. Menon believes his beamsplitter could be used in those computers in about three years.
Menon and colleagues describe their work in the journal, Nature Photonics.