a broadband single polarization photonic crystal fiber filter around 1.55 μm based on gold-coated and pentagonal structure

In this paper, a broadband single polarization photonic crystal fiber (pcf) filter around 1.55 μm is presented on account of surface plasmon resonance. the finite element method is used to investigate the performance of the filter, and the structure parameters’ influences on the performances of the filter are studied. due to asymmetry which is caused by the pentagonal arranged cladding air holes, the confinement loss of the y polarization core mode reaches to as high as 1751.05 db/cm around 1.55 μm, while the loss for the x polarization mode is only 0.22 db/cm. this indicates that a loss ratio of 7959.32 is achieved and the crosstalk value is up to 304.15 db with 200 μm pcf around 1.55 μm. moreover, the bandwidth of 20 db crosstalk value is 1010 nm with a wavelength coverage from 1.39 to 2.40 μm. numerical simulations also show that the designed filter has good tolerance to structural deformation. therefore, the proposed pentagonal filter has great potentials in the application of broadband communication system.