Scheme of a waveguide-integrated plasmonic nanoantenna for mode-selective polarization (de)multiplexing. The device couples light of orthogonal polarizations into different directions and modes of the underlying silicon waveguide. Credit: Science Advances (2017). DOI: 10.1126/sciadv.1700007
(Phys.org)—A team of researchers from several institutions in Germany and Australia has developed an optical high-bitrate nanoantenna that they used with an optical waveguide. In their paper published on the open access site Science Advances, the team explains how their device works and their plans for improving it to make it more commercial.
Imprinting an optical nanoantenna onto an optical waveguide, as the researchers note, is still a new idea—most such efforts have involved devices that couple light to a waveguide mode. In this new effort, the researchers have advanced the idea with a device capable of sorting and routing streams of information that has been encoded into a beam of light using varying polarizations. What's more, they have found a way to do it using optical components that are much smaller than other devices—down to sub-micrometer size, which opens the possibility of high-density photonics components on a chip. They report that their device is capable of directional, polarization-selective and mode-selective routing on a silicon rib waveguide. Their efforts, they note, demonstrate that nanoantenna integration into waveguides holds the potential for developing new high-bitrate telecommunications applications.
An optical nanoantenna works by taking advantage of plasmonics—light striking a metal causes electrons on the surface to move in plasmon waves. These have wavelengths that are smaller than the smallest light wavelength, which means researchers can create devices so small that they are able to convey information using photons. One of the goals of researchers in this field is to create integrated circuits that process and move information using photons instead of electrons. Achieving such a goal requires optical waveguides capable of routing information represented by photons.
"Our invention can be used to connect these processors with optical wires that will transmit data between processers thousands of times faster than metal wires. This will enable smooth rendering and large-scale parallel computation needed for a good gaming experience." Credit: Australian National University
The new device was created using extremely small gold bars, which, the team notes, presents a problem for commercialization—the precious metal must be replaced with another to make it CMOS compatible. The team also plans to improve the transmission efficiency of their device, and are considering attempting to create circuits by joining their devices together.
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