Dispersion and polarization properties in photonic crystal fibers

Systematic knowledge of the particular guiding properties of photonic crystal fibers (PCF´s) permits the achievement of structures with flattened, or even ultraflattened, positive, negative, or nearly-zero group velocity dispersion for different wavelength ranges. On the other hand, we have identify a PCF, called super-square PCF, in which the introduction of an off-lattice hole generates a highly anisotropic intraband guidance, and then the structure operates as a polarization maintaining fiber. Moreover, the combination of this anisotropy and intraband guidance gives rise to a radically new mechanism of polarization discrimination, which leads to a new class of single-polarization single-mode fibers. In both cases the goal is to control the dispersion and polarization properties in PCFs by modifying solely the geometrical parameters of these fibers. Keywords: fiber design, flattened dispersion.