Abstract

When an optical fiber is immersed in a fluid (liquid or gas), ultrasonic waves propagating in the fluid cause phase shifts in the light propagating in the fiber predominantly through radial strains since inertial effects do not permit a net axial strain contribution. We have studied the ultrasonic sensitivity of single-mode fibers by taking into account the exact composition and geometry of multilayer fibers in the isotropic regime (where the acoustic wavelength is much larger than the fiber diameter) and In the anisotropic or high-frequency regime (where the reverse is true). Good agreement was found between analysis and experiments, and coating compositions optimizing the ultrasonic sensitivity have been identified.

© 1985 Optical Society of America