Switchable fiber-optic tap using acoustic transducers deposited upon the fiber surface

A new electronically switchable fiber-optic tap is demonstrated. The tap consists of an array of acoustic transducers fabricated directly upon the side of a cylindrical single-mode fiber. The transducer array generates an acoustic field that is focused on the fiber core and that satisfies the Bragg condition, allowing light to be deflected out of the fiber by the acousto-optic Bragg interaction. The amount of light tapped is linearly proportional to the rf power driving the transducer array. The bandwidth of the tap is 920 MHz centered at 3.3 GHz, with a maximum tap efficiency of 0.4% per watt of rf input.