The Research Of Photonic Crystal Fiber With Flattened Dispersion And High Birefringence

Optical fiber communication has become the main pillar of modern communicationand play a decisive role position in modern communication network, fiber is the maintransmission medium. Photonic crystal fiber, as a novel fiber, which was first fabricated in1996,have attracted much attention from academic circle of the world due to its uniqueproperties compared with the conventional fibers, such as endless single mode, highbirefringence, low confinement loss, flattened dispersion. So it is important to study thecharacteristics and applications of PCF. The paper focus on the design and applications onPCF, the main work are as following.(1)We introduced different kinds of novel features of PCF, and the most common used indrawing PCF—packing method and its process.(2)We use full vector finite element method, plane wave expansion method andanisotropic perfectly matched layer, provide theory and mathematical basis for structuredesign of crystal fiber.(3)We design a novel square-lattice PCF with hybrid cladding according to variationcharacteristics of PCF，then analyse the influence of structure parameters on dispersion,confinement loss, and obtain the optimal parameter values. The fiber own ultra-flattenedchromatic dispersion from1.32nm to1.64nm (320nm band), and the confinement losses areless than10-7dB/m, meanwhile the PCF that we proposed is robust to small fabricationimperfections.(4)A perfect single-mode property and high birefringence PCF is proposed. By filling thesilica into one line elliptical air holes parallel to x-axis and rotated by an angle of θ=45°,meanwhile introducing one line elliptical air holes parallel to y-axis without any material androtated by an angle of θ=45°to other direction, so it can break the symmetry of the PCFstructure dramatically in order to obtain high birefringence. The result indicates that ourproposed PCF can obtain the highest modal birefringence of4.65×10-2at the wavelength of1.55μm, the cut-off wavelength is only0.6122μm, at the same time the confinement losses are less6.4×10-6dB/m at1.55μm.