Update on free-space optics

Monday, November 01, 2004

A Penn State University electrical engineer says clouds and fog need not be an obstacle to using optical signals to transmit voice, video or computer data through the air.

Speaking at the Optics East 2004 Conference in Philadelphia last week, Mohsen Kavehrad said a system encodes data as ultra-short laser pulses, which don't interact readily with rain or fog. The same data is then transmitted simultaneously at different signal rates to increase the odds of the signals getting through. Lower rate signals, for instance, may penetrate clouds that high rate signals can't.

These optical wireless systems, known as free-space optics, could be used for battlefield communications between air and ground vehicles, or for connecting scattered buildings into a computer network.