Switchable fiber-optic tap using the acousto-optic Bragg interaction

A new type of electronically switchable optical-fiber tap using acousto-optic Bragg diffraction is demonstrated. An acoustic transducer on a wedge launches an acoustic beam through a Hertzian contact into a D-shaped optical fiber, diffracting light out through the side of the fiber. The bandwidth of the tap is greater than 1 GHz centered at 3.5 GHz, with a tap efficiency of 0.01% per watt of rf power. The tap does not damage the fiber and is completely reversible, so its location on the fiber can easily be adjusted.