Intel researchers have produced an optical chip that could help revolutionize computer communications by making it affordable to connect computers with fiber optics over short distances.
The new chip houses a device called an optical modulator. Similar devices are used today to transform the digital 1s and 0s in electrical data into optical pulses that are then sent around the world, forming the backbone of the Internet and long-distance phone lines. But the materials that current devices are made from, such as lithium niobate, are too expensive to replace the cheap copper wires that connect most computers in home and office networks. To find a cheaper substitute, Intel and other chip companies have begun working to make all of the critical components needed for an optical network out of silicon, so networking devices could be produced in the same high-volume fabrication facilities that currently turn out electronic chips by the billions.
Researchers have been working on silicon modulators for years, but the devices have been much slower than commercial ones. Now, a team led by optics researcher Ling Liao of Intel's lab in Santa Clara, California, has used a silicon modulator to achieve pulse speeds of 10 Ghz--comparable to standard telecommunications modulators. To boost the speed, Liao and her colleagues improved the ability of their devices to manipulate laser light. The silicon modulator splits laser beams into two channels, where the light waves can be manipulated to either cancel each other out (0) or travel side by side (1) when recombined. The Intel team, which reports its results in today's issue of Optics Express, came up with a series of manufacturing techniques to replace a layer of tiny silicon grains that slowed down previous modulators with crystalline silicon, allowing the device to cycle on and off more quickly.
"This is quite big news," says Graham Reed, a silicon photonics researcher at the University of Surrey in the United Kingdom. Critics of silicon optics, Reed says, have continued to argue that silicon will never make a useful optical material. "Now all the skeptics will start to believe that silicon will have a real impact."
The study