Engineers take step toward photonic circuits
The invention of fiber optics revolutionized the way we share information, allowing us to transmit data at volumes and speeds we’d only previously dreamed of. Now, electrical engineering researchers at the Univ. of Alberta are breaking another barrier, designing nano-optical cables small enough to replace the copper wiring on computer chips.
This could result in radical increases in computing speeds and reduced energy use by electronic devices.
“We’re already transmitting data from continent to continent using fiber optics, but the killer application is using this inside chips for interconnects—that is the Holy Grail,” says Zubin Jacob, an electrical engineering professor leading the research. “What we’ve done is come up with a fundamentally new way of confining light to the nanoscale.”
At present, the diameter of fiber optic cables is limited to about one thousandth of a millimeter. Cables designed by graduate student Saman Jahani and Jacob are 10 times smaller—small enough to replace copper wiring still used on computer chips.
Capturing all the light, without the heat
Jahani and Jacob have used metamaterials to redefine the textbook phenomenon of total internal reflection, discovered 400 years ago by German scientist Johannes Kepler while working on telescopes.
Researchers around the world have been stymied in their efforts to develop effective fiber optics at smaller sizes. One popular solution has been reflective metallic claddings that keep light waves inside the cables. But the biggest hurdle is increased temperatures: metal causes problems after a certain point.
“If you use metal, a lot of light gets converted to heat. That has been the major stumbling block. Light gets converted to heat and the information literally burns up—it’s lost.”
Jacob and Jahani have designed a new, non-metallic metamaterial that enables them to “compress” and contain light waves in the smaller cables without creating heat, slowing the signal or losing data. Their findings appear in Optica.
Source: Univ. of Alberta