14 Ekim 2007 Pazar
Silicon-based Light Detector
Technology Review's article
Researchers at Intel recently announced a silicon-based light detector that, by all measures, is better than those made of more expensive materials. It can detect flashes of light at a rate of 40 gigabits per second, while most of today's fiber-optic networks operate at 10 gigabits per second. The new detector is also more efficient and produces a cleaner signal than other detectors that operate at the same speed. Since detectors made of silicon have the potential to be manufactured on large silicon wafers, through standard processing techniques, researchers could produce detectors that are hundreds of times less expensive than those used in today's networks, which are made of materials such as indium gallium arsenide.
Intel's silicon detectors use the same basic principles that many other light detectors do, explains Paniccia. When photons strike a traditional detector, they produce pairs of electrons and "holes." (A hole is the absence of an electron where one would be expected; it can be thought of as a positively charged particle.) A voltage is applied across the detector, pushing the negatively charged electrons one way, and the positively charged holes the other way. The resulting electrical current provides a measure of the amount of light the detector collected.