Silver layer thickness insensitive index sensor based on hollow core photonic crystal fiber

We propose a silver layer thickness insensitive index sensor based on silver coated on the inner wall of the HC-PCF. Under the boundary condition of anisotropic perfectly matched layer (PML), a full-vector finite element method (FEM) is used to calculate the fiber model. Numerical results indicate that the excitation of the plasmon mode is sensitive to the change of the refractive index of the adjacent analyte. The confinement loss of the core guided mode increases when both the refractive index of the analyte and the thickness of the silver film do. The maximum spectral sensitivity of the sensor can be 7330 nm/RIU. Furthermore, the spectral sensitivity of the sensor doesn't approximately change when the thickness of the silver film increases.