Polarization-mode coupling along a polarization-maintaining holey fiber

We use the dramatic change in modal birefringence with wavelength seen in holey fibers (HFs) to examine the polarization-mode coupling that occurs along the fiber. This mode coupling is successfully observed using an interferometric method at the wavelengths of 823, 973, 1312, and 1547 nm. We investigate the relationship between the coupling coefficient and propagation constant difference for two orthogonally polarized modes. The Lorenzian power spectrum model, originally proposed for elliptical-core, elliptical-cladding, and PANDA fibers, well matches the experimental data for HFs with large birefringence values