Parametric analysis of elasto-optic birefringent axis alignment in eccentrically coated polarization-maintaining optical fiber.

When high-birefringent fibers are used in polarization-sensitive devices, one must ensure the proper alignment of the optical axes. One nondestructive alignment method involves squeezing the fiber and noting the change in the resultant birefringent axes. We use the finite-element method to determine the change in the principal stress direction, and, hence, the extrinsic birefringent axis orientation, as a function of the fiber coating eccentricity. Fiber eccentricity can shift the extrinsic birefringent axis by more than 1.5 degrees , whch becomes important in high-performance device applications.