Surface plasmon induced dual-wavelength photonic crystal fiber polarizing filter based on coupling between core mode and SPP mode

Abstract

A dual communication band photonic crystal fiber polarizing filter based on coupling between core mode and SPP mode is proposed in this paper. By optimizing the parameters of the fiber structure, the resonant points can be tuned to the communication band. Numerical simulation results demonstrate that the resonance strength of x- and y-polarized direction can simultaneously reach 729.47 and 542.78dB⋅cm−1 at the communication wavelength of 1.55 and 1.31 μm. By filling liquid analyte the confinement loss of x- and y-polarized direction can simultaneously reach 580.55 and 714.48dB⋅cm−1 at the wavelength of 1.55 and 1.31 μm. Furthermore, when the fiber length of L is equal to 700 μm, the peak value of the crosstalk can reach 421.89 and −322.34 dB at the same time at the wavelength of 1.31 and 1.55μm, and when the length of the fiber L is 400 μm, the bandwidths of the crosstalk better than 20 dB and less than −20 dB are about 170 and 220 nm, respectively. These properties make it an ideal candidate for designing dual-band polarization filter equipment.