The role of acoustic properties in designs of acoustic and optical fibers

Abstract

Spatial distribution profiles of leaky surface acoustic wave velocity ν LSAW and attenuation α LSAW across the diameters of clad fibers made of pure or doped fused silica glasses are presented. The profiles are obtained by using a V(x,z) analysis with a reflection scanning acoustic microscope operated at 775 MHz, and are compared with optical refractive index profiles. The V(x,z) plane is defined by continuous recording to V(z) curves while scanning an arbitrary x axis along the surface of the sample. Optical fibers of different dopants and dopant concentrations have been investigated. It is demonstrated that the ν LSAW profile across the fiber diameter can be used as an alternative for those of bulk longitudinal and shear wave velocities. The role of such acoustic profiles across the core and cladding regions in characterizing several optical fiber devices is outlined. Acoustic fibers have become very attractive candidates for integrated acoustic components owing to the recent advent of long length single crystal LiNbO 3 fibers. The acoustic characterization of doped LiNbO 3 single crystals is illustrated.