Polarization dependence of photo-induced birefringence and its application to fabrication of tailored polarization filters

Photo-induced anisotropy has been observed in optical fibers exposed to polarized blue-green1-4 and U.V. light6-10. The control of the fiber birefringence has permitted the fabrication of polarization rocking filters, which have found use in both sensing and communication applications. The physical mechanism underlying this effect is thought to be the preferential excitation and depletion of those anisotropic defects whose polarizability is aligned with the incident field polarization, causing a reduction of polarizability along that direction3,4,11. In this paper, we study the polarization dependence of photo-induced birefringence in elliptical core fibers and, as a consequence, propose a technique for fabrication of polarization rocking filters with tailored coupling spectrum.