Perturbation effects on mode propagation in highly elliptical core two-mode fibers

The propagation of both fundamental and second-order modes in highly elliptical core two-mode fibers under external perturbations is investigated. Theoretical and experimental results are presented for the differential phase shift between two spatial modes in each eigenpolarization and the polarization behavior of each spatial mode. The perturbations include axial strain, radial strain, hydrostatic strain, temperature change, twisting, squeezing, and bending. An application of the modal behavior of these fibers to simultaneous measurement of strain and temperature is described.<
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