World's smallest beamsplitter paves way toward computing at the speed of light

Silicon photonics is an emerging technology that incorporates electronic circuits using photons of laser light ratherthan electrons to transmit, receive, and manipulate information. As such, a silicon photonic CPU could potentiallyprocess information at the speed of light – millions of times faster than computers available today. In a step towards this goal, engineersworking at the University of Utah have developed an ultra-compact photonic beam-splitterso small that millions of these devices could fit on a single silicon chip.

The beamsplitter,claimed to be the smallest ever created at just 2.4 by 2.4 microns (aboutone-fiftieth the diameter of a human hair), is designed to divide incoming lightwaves in two, thereby creating two separate channels of separately polarized information. Combined with other photonics components that replace their electronic equivalents, such as transistors, diodes, and other semiconductor devices, the beamsplitter adds to the growing catalog of devices being created for future photonic computing.

"Lightis the fastest thing you can use to transmit information," said associate professor in electrical and electronic engineering at the University of Utah, Rajesh Menon."But that information has to be converted to electrons when it comes intoyour laptop. In that conversion, you're slowing things down. The vision is todo everything in light. With all light, computing can eventually be millions of times faster.”

Dan Hixson/University of Utah College of Engineering

Not onlyis the new device theoretically capable of helping to exchange data at blistering speeds,but its silicon-based design means that it would also be cheaper and easier to makethan similar devices because it could use existing silicon chip fabrication techniques. Inaddition, because photonic circuitry does not require the movement of electronsthrough wires, devices containing such technology would use a lesser amount ofpower and generate less heat, making them considerably more efficient.

Supercomputerscurrently under development at Intel and IBM using silicon photonics are thetarget of the University of Utah’s team. They believe that their beamsplittercould be ready for use in such computers within about three years, and thatdata centers needing faster connections may well incorporate such devices evensooner.

The resultsof this research by associate professor Rajesh Menon, in collaboration with research associate Randy Polson and doctoral studentsBing Shen and Peng Wang have recently been published in the journal NaturePhotonics.

Source: University of Utah