Design of offset core photonic crystal fiber filter based on surface plasmon resonance

The novel offset core photonic crystal fiber filter is designed and analyzed, whose dispersion relations and polarization characteristics are simulated by finite element method using COMSOL Multiphysics software. The filter structure is optimized by changing diameter of air holes and the thickness of Au layer. Simulation results show that loss of y-polarized mode reaches 657 dB/cm while the loss of x-polarized mode is very low at the communication window ($1.55\mu \text{m}$). The crosstalk of filter reaches 56.2 dB at $1.55\mu \text{m}$ wavelength and the 20 dB band width of the filter is 100 nm when the propagation distance is $1\mu \text{m}$. Not only the filter shows good performance but also the proposed photonic crystal fiber can be applied to other fields.