High sensitivity surface plasmon resonance sensor based on D-shaped high birefringence photonic crystal fibre

A sensitivity refractive index (RI) sensor based on surface plasmon resonance (SPR) effect in D-shaped high birefringence photonic crystal fibre (PCF) is presented and studied by the finite element method (FEM). Through the designing of air holes arrangement in PCF, the birefringence of optical fibre is improved and the SPR effect of y-polarized core mode is directionally excited. The designed D-shaped PCF with gold film in the damaged air holes enhances the interaction of the evanescent field with the external medium. Simulation results indicate that the sensor has a sensing range from 1.30 to 1.37, and the average spectral sensitivity is 10348.3 nm/RIU. The maximum spectral sensitivity of 19,288 nm/RIU and a high resolution of 5.18 × 10−6 RIU can be obtained at 1.37. This high sensitivity sensor has broad application prospects in life science and other research fields.