Saturday, February 11, 2012

MIT Developing Photonic Chips

There has been enormous progress made in recent years to develop photonic chips that use light beams instead of electrons to carry out computational tasks. Now, researchers at MIT with funding from the National Science Foundation (NSF) have filled in a crucial piece of the puzzle to enable the creation of photonic chips on standard silicon material to form the basis for most of today’s electronics.

Development of the technology would greatly boost the speed of data-transmission systems for two reasons. First, light travels much faster than electrons and secondly, while wires can only carry a single electronic data stream, optical computing enables multiple beams of light carrying separate streams of data to pass through a single optical fiber or circuit without interference. “This may be the next generation in terms of speed for communications systems, reports Caroline Ross, the Toyota Professor of Materials Science and Engineering at MIT.

In many of today’s communication systems, data travels through light beams transmitted through optical fibers. Once the optical signal arrives at its destination, it is converted to electronic form, then goes through electronic circuits, and then is converted back to light using a laser. Development of the new device could eliminate those extra electronic conversion steps, allowing the light signal to be processed directly.

“The new component is a diode for light,” says Ross and the co-author of a paper reporting on the new device that was published online November 13th in “Nature Photonics”. According to Ross, it is analogous to an electronic diode, a device that allows an electric current to flow in one direction but blocks it from going the other way. In this case, it creates a one way street for light rather than electricity.

“The whole system could be made using standard microchip manufacturing machinery” said Ross. “This would make it easier to commercialize than a system based on different materials.” She points out that there is a huge infrastructure for silicon processing and the process used is well known. This means that the chip can be developed without worrying about new fabrication techniques.”