Intel connects chips with optical fiber

Intel's Components Research Lab is working on ways to replace copper wiring between motherboards and chips inside computers with faster, more energy-efficient optical fiber.

The lab has created a prototype system with chips connected to each other through eight optical channels transferring data at more than 1 gigabit of data per second for an aggregate bandwidth of over 8gbps (gigabits per second). The individual channels, called waveguides, can transfer data at up to 3gbps.

That's slower than conventional optical technology--and even some standard connections in PCs today--but the entire unit is housed inside a chip package and should be cheaper than current optical parts. And eventually it will speed up, Intel said.

The effort is largely aimed at dodging some of the problems looming with metal interconnects and buses. Channels in PCI Express--a faster connection for shuttling data within a PC--can pass data at 2.5gbps, but metal channels will likely top out at 10gbps and 20gbps because of signal attenuation and other problems, said Ian Young, director of advanced circuits and technology integration at Intel's lab.

"We are going to start to have trouble (with copper interconnections) at 10 gigabits," he said. "As frequency increases, optical attenuation occurs much more slowly than electrical attenuation."

Optical chip company Primarion is working on similar technology. Both Intel and Primarion started examining optical interconnects a few years ago.

Fiber is currently being used to connect servers, but it will likely begin to connect boards inside computers in two to seven years. Chip-to-chip optical connections will start to appear in about seven years, Young said.