Shanghai's Fudan University announced on Friday that a hydrophone developed by its professors with optical-fiber technology had been successfully applied in the National Aquatics Center for the Olympic Games water ballet.

Swimmers rely on underwater speakers when immersed in water to pick up the beat and dance gracefully. It causes big performance problems when speakers function abnormally or break down.

A hydrophone is a microphone designed to be used underwater and thus can monitor the sound of underwater speakers and provide vital information for referees and staff.

The hydrophone is the next step up in technology from underwater speakers and video cameras.

An optical fiber is a glass or plastic fiber, smaller than a human hair that permits transmission over longer distances and at higher data rates than other forms of communications

"We curled about 10 meters of optical fiber into a coil and put it on one wall of the swimming pool," said Tang Huang, a research team member.

The coil was linked to a machine weighing less than 4 kilograms at ground level to interpret information.

"The fiber-optic hydrophone has been used widely in military affairs," said Tang. "This is the first time that such technology has been used in an Olympic Games."

(Shanghai Daily August 24, 2008)