Design of Photonic Crystal Fiber Filter With Narrow Width and Single-Polarization Based on Surface Plasmon Resonance

In this paper, we present a photonic crystal fiber (PCF) filter that it has the advantageous properties of narrow width and single-polarization through the principle of surface plasmon resonance (SPR) by a full-vector modal solver based on the finite element method. Gold nanowire is used as the SPR active metal and be filled into cladding air holes selectively. The proposed PCF can be used as a perfect polarization filter at 1.31 or 1.55 μm from y-polarized mode, respectively, if the appropriate sizes of the cladding air holes are selected. Only 13 nm that the full width at half maximum is able to achieve with one gold nanowire, and when the PCF is filled two gold nanowires, with a length of 1 mm of the designed PCF, the bandwidths with the crosstalk better than 30 dB can reach up to 235 nm, at the wavelength of 1.55 μm. The results indicate that the polarized light in one direction can be filtered out selectively by adjusting diameter of air holes and achieve filtering effect in communication bands.