Within the next few years, computer chips will process data so rapidly that the wires carrying information between them will have difficulty keeping up. One possible solution is to transport the data using laser beams that blink on and off billions of times a second. Ling Liao, of Intel's Photonics Technology Lab, is bringing us closer to that goal by figuring out how to build key optical components from the same silicon used to make the rest of a computer chip. That would make integration simpler and bring down costs.
But silicon is normally a poor optical material; it's particularly hard to get silicon to modulate light--that is, to induce the blinking effect that encodes data. More exotic materials can make light fluctuate in response to a changing electric field, but silicon resists that approach. Liao found that if she put a thin layer of silicon dioxide between two slabs of silicon, she could quickly make electrons accumulate on both silicon surfaces, and remove them quickly as well. That alters any light waves that pass through the silicon, making them either dimmer or brighter. By building up and then releasing the charges using an alternating voltage, she can modulate light at 10 gigabits per second, and shes working on ever faster speeds. It may be a decade before her device finds its way into your computer, but eventually optical connections may be able to handle speeds hundreds of times faster than those seen in today's PCs.
--Neil Savage
