Graphene-Photonic Crystal Fiber Biodetection Based on Surface Plasma Resonance Effect and Defect Coupling

In this paper, we propose a defect coupled photonic crystal fiber (PCF) biosensor detection method. A double-layer annular pore array with different diameters is designed, which is characterized by six periodically arranged holes (d1=0.7um) in the inner layer of the core and five symmetrically arranged holes (d2=0.8um) in the outer layer. By removing two air holes to form defects, the evanescent field leakage to the pore defects can be effectively enhanced. By using the finite element method (FEM), the sensing performance can be greatly improved by optimizing the geometric structure parameters, metal thickness and adding graphene. When the refractive index of the measured medium changes from 1.33 to 1.37, the sensitivity of the sensor can be improved to 3000nm/RIU.