Numerical Analysis of Polarization Filter Characteristics of D-Shaped Photonic Crystal Fiber Based on Surface Plasmon Resonance

In this paper, a novel D-shaped photonic crystal fiber (D-PCF) based on surface plasmon resonance (SPR) is designed, and gold nanowire is used as the SPR active metal. A full-vector finite element method is applied to analyze the polarization filter characteristics. Phase matching between the second-order surface plasmon polariton (SPP) mode and the core-guided modes of x- and y-polarization can be met in two different wavelengths. By adjusting the diameters of the large air holes and the gold nanowire, this designed D-PCF can be used to the polarization filter in two communication bands. The loss of unwanted y-polarization mode can reach 244.9 and 292.8 dB/cm at the wavelength of 1.31 and 1.55 μm, respectively. With a length of 1 mm of the designed D-PCF, the bandwidths with the crosstalk better than 30 dB can reach to 88 and 150 nm, and the crosstalks are 208.4 and 249.5 dB the wavelength of 1.31 and 1.55 μm, respectively.