Computing at the Speed of Light

The world of computing could change rapidly in coming years thanks to technology that replaces the metal wiring between components with faster, more efficient fiber-optic links.

Seeing the light: A chip in the center of this circuit board contains four lasers that convert electrical signals into light pulses. The pulses travel at high speeds along a fiber-optic link. Credit: Intel

“All communications over long distance are driven by lasers, but you’ve never had it inside devices,” says Mario Paniccia, director of Intel’s photonics lab in Santa Clara, CA. “Our new integrated optical link makes that possible.”

Paniccia’s team has perfected tiny silicon chips capable of encoding and decoding laser signals sent via fiber optics. Today, when data arrives at a computer via a fiber optic connection it has to be moved from a separate photonic device to an electronic circuit. This new system promises to speed things up because everything works in silicon.
Last week, Paniccia’s team demonstrated the first complete photonic communications system made from components fully integrated into silicon chips. Electronic data piped into one chip is converted into laser light that travels down an optical fiber and is transferred back into electrical signals a few fractions of a second later. The system can carry data at a rate of 50 gigabytes per second, enough to transfer a full-length HD movie in less than a second.
The silicon photonic chips could replace the electronic connections between a computer’s key components, such as its processors and memory. Copper wiring used today can carry data signals at little more than 10 gigabytes per second. That means critical components like the central processing unit and the memory in a server cannot be too far apart, which restricts how computers can be built.
The new Intel setup has four lasers built into its transmitter chip that shine data into a single optical fiber at slightly different wavelengths, or “colors.” Chips with even more lasers should make it possible to communicate at 1,000 gigabytes per second.
“Having a chip the size of your fingernail that can deliver a terabit per second changes the way you can think about design,” says Paniccia. Such chips could make a big difference inside the sprawling data centers operated at great expense by Web giants like Google, Microsoft, and Facebook. “Data centers today are big piles of copper–that imposes the limits on how you arrange components inside a server,” Paniccia says.