Interferometric stain measurement by arbitrarily configured surface-mounted, optical fibers

The phase change of light traveling in a single-mode, arbitrarily configured optical fiber when the fiber is subjected to an arbitrary strain field is described by an integral equation. Assumptions concerning strain transfer from the strained body to a surface mounted optical-fiber sensor are experimentally verified. The general mathematical description is applied to two interferometric optical-fiber strain sensor geometries and is verified by experiment. The lack of precise data about the mechanical and optical material properties of the fiber is circumvented through calibration. Extensions of this model to both embedded fibers and nonlinear fiber response are discussed.<
>