Structure Design And Characteristics Analysis Of The Dual-core Photonic Crystal Fiber

As researchers have taken more attention on theoretical research, characterization,production methods and other aspects of silica glass photonic crystal fiber, the theory ofsilica glass photonic crystal fiber continues to improve, and the researchers graduallystudy the soft glass photonic crystal fiber. The soft glass have many advantageousproperties, such as expanding the range of the transmission band, having a highernonlinearity coefficient, the greater the solubility of rare earth ions, lower melting pointand so on, corresponding to the silica glass. Compared with the traditional dual-core fibers,dual-core photonic crystal fibers have the advantages of the flexible structure design andsimple production process, in that case the photonic crystal fibers have great potentialapplications in optical device, such beam couplers, splitter, WDM and so on. The keyworks of this paper can be described as follows:The characteristics of the dual-core photonic crystal fiber can be investigated byusing the full-vector finite element method and Beam propagation method, we analyzedimpacts of structural parameters on the birefringence and the coupling length withCOMSOL Multiphysics software and RSoft software.Based on the coupling mode effect, a novel duel-core photonic crystal fiberpolarization beam splitter with dual elliptical air holes around the fiber core was proposed.Using the full-vector finite element method (FEM), we analyzed impacts of structuralparameters on birefringence and coupling length. Numerical simulations demonstratedthat the birefringence decreases as the value of hole-pitch increases, but the couplinglength increases as the value of hole-pitch increases; the birefringence increases as thevalue of ellipticity increases, but the coupling length decreases as the value of ellipticityincreases; the birefringence decreases as the value of air hole diameter decreases, thecoupling length decreases as the value of air hole diameter decreases. By optimizing thegeometric parameters of the proposed dual-core photonic crystal fibers, a dual-core PCFwith high birefringence and low coupling length is obtained.A novel kind of tellurium glass octagonal dual-core photonic crystal fiber is proposedin this paper. We investigate the influence of geometric parameters on the coupling lengthand relative coupling length with the full-vector finite element method (FEM). Numerical simulations demonstrated that the coupling length decreases as the value of hole-pitchdecreases, but the relative coupling length decreases as the value of hole-pitch decreases;the coupling length increases as the value of air hole diameter increases, the relativecoupling length increases as the value of air hole diameter increases; the coupling lengthincreases as the value of ellipticity increases, the relative coupling length increases as thevalue of ellipticity increases. By optimizing the geometric parameters of the proposeddual-core photonic crystal fibers, a polarization beam splitter with idea performance isobtained. In addition, the tellurium glass splitter exhibited high performance of splittingone light into two orthogonal polarization states, compared with the SF6glass splitter.