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Bright Idea

Engineers Hugh Popenoe, Norm Farr, and Terry Hammar test a new optical modem system for the first time in the fall of 2006 on the dock in Woods Hole, Massachusetts. The WHOI-developed system will use light signals to send data—at a rate of 10 megabits per second and at ranges up to 100 meters—between autonomous underwater vehicles and the nodes of ocean observatories, much like a computer sends electrical data through copper phone lines. The engineers from the Applied Ocean Physics and Engineering Department chose blue light (shining from below the water line) for the modem system because it transmits through water better than other light wavelengths. The yellow hard hat—being lowered into the water—contains the reciever. (Photo by Tom Kleindinst, Woods Hole Oceanographic Institution)