Ultra-wide bandwidth polarization filter based on gold-coated photonic crystal fiber around the wavelength of 1.55 μm

A novel ultra-wide bandwidth photonic crystal fiber (PCF) polarization filter based on surface plasmon resonance (SPR) is proposed. The PCF has two large cladding air holes in the direction of y-axis that are selectively coated with gold films to create resonance. There are two small holes in the direction of x-axis, which provides high birefringence. The polarization characteristics of PCF are studied by finite element method (FEM). The numerical simulation results indicate that the loss of y-polarized core mode is 718.87 dB/cm, while the loss of x-polarized core mode is only 0.95 dB/cm at the resonant wavelength of 1.55 mu m. The extinction ratio is better than 20 dB at the wavelength ranging from 1.43 to 1.79 mu m, the corresponding bandwidth is 360 nm. (C) 2018 Elsevier Ltd. All rights reserved.