Deposition of oriented zinc oxide on an optical fiber

Techniques are described by which an oriented zinc oxide film is sputtered directly on one side of an 80-μm-diam fused silica single-mode optical fiber. A 4-GHz piezoelectric transducer incorporating this film demonstrates that the film is oriented. Evidence of acoustic waves in the fiber is given by the swept-frequency vector input impedance of the transducer. Acoustic transducers fabricated directly on a fiber produce fields focused on the fiber core for efficient acousto-optic interactions, making possible many new fiber-optic signal processing devices.