Computing at the Speed of light ( part 2 )

Further savings may come from the fact that optical links require less power to operate, says Keren Bergman, who leads a silicon photonics research group at Columbia University. "With electrical wires, the longer you go, the more energy you spend in an exponential fashion," she says. Optical fiber allows low-power signals to travel farther faster. Bergman's group has used data on the performance of computers at Lawrence Berkeley and MIT's Lincoln Laboratories to simulate how systems with optical interconnects might perform. "You can get an order of magnitude gain in energy efficiency," she says, with the largest gains seen for applications such as high-bandwidth image processing and video streaming, she says.

Data centers aren't the only things that may see their insides lit up with lasers. "We've developed this technology to be low-cost so we can take it everywhere, not just into high-performance computing or the data center," says Paniccia. The components of the Intel system, including the lasers, are made with the same silicon-sculpting methods used to construct computer chips in vast quantities. "I'm drafting Moore's law," says Paniccia. "We've enabled the benefits of using light with the low-cost, high-volume, scalability of silicon."In consumer computers like laptops, that would allow innovations in industrial design. I could put the memory in the display instead, and change the design of the whole thing."

This could make it easier to swap in new components without having to open up a machine. It would also allow core components to be installed in peripherals. Extra memory could, for example, be hidden in a laptop or smart phone dock to increase a portable device's computing power when plugged in.

Fully exploiting the benefits of the optical age will, however, means changes to the components being linked up. "It's not just a case of whip out the electrical wires and replace them with optical fiber," says Bergman.

Ajay Joshi, an assistant professor at Boston University, who is also exploring design options for high-performance computers with optical interconnects, agrees. "If we speed up the channel between logic [processors] and memory, we need to rethink the way you design that memory."

The speed gap between processors and optical links is smaller, but ultimately, that too will likely change. "It would be nice to also see processors that work optically instead of electronically," Joshi says