Single-polarization single-mode intraband guidance in supersquare photonic crystals fibers

We present a two-dimensional (2D) photonic crystal structure exhibiting appealing guiding properties as an optical fiber. The structure can be regarded as a dislocation of a variant from a 2D square photonic crystal and shows a large photonic band gap for on-axis illumination. The introduction of an off-lattice hole in the structure acts as a defect and generates a highly anisotropic intraband guidance. The combination of very strong anisotropy and intraband guidance gives rise to a mechanism of polarization discrimination in optical fiber propagation that enables this guiding structure to operate as a single-polarization single-mode fiber over a wide wavelength window.