Polarizing photonic crystal fibers for different operation range

We have experimentally characterized three polarizing photonic crystal fibers manufactured by the Laboratory of Optical Fiber Technology, Maria Curie-Sklodowska University, Lublin, Poland. In the investigated structures the dissimilarity in the cut-off wavelengths is induced by a pair of large air holes adjacent to the fiber core. Because of different geometry, the investigated fibers have different polarization ranges. In the first structure, the polarization dependent loss (PDL) of 3 dB/m is observed at 1300 nm and further increases against wavelength. In the two other fibers, the polarization bandwidth is shifted towards longer wavelengths. We have also investigated the effect of bending on polarization characteristics. It was experimentally demonstrated that for bent fiber the attenuation of the LP_y ⁰¹ increases for shorter wavelengths, which results in wider polarization bandwidth. Moreover, we have numerically analyzed and optimized for maximum operation bandwidth two constructions of the index guided PCFs, whose polarization properties are induced by unequal diameters of the cladding holes.