A high sensitivity refractive index sensor based on microstructure fiber with simple structure and SPR effect

A novel dual-side polished photonic crystal fiber (PCF) based surface plasmon resonance (SPR) polarization filtering and refractive index (RI) sensor is presented in this paper. The cladding of PCF was composed of eight air holes and the outer surface was dual-sided polished and coated with gold film. Finite element method (FEM) was used for the simulation and design of the proposed sensor. Simulation results showed that sensor performance was better in analytes ranging from 1.33 to 1.42 RI. The wavelength and amplitude sensitivities at resonance wavelengths of 1269 and 995 nm were 27400 nm/RIU and -100.43 RIU-1 for an analyte of 1.42 and 1.41 RI, respectively, along with a spectral resolution of 3.64x10-6 RIU. Maximum loss of 52806 dB/m was obtained for an analyte of 1.41 RI towards Y-Polarization (Y-P). An extinction ratio of -105.374 dB was obtained using a fiber transferring length of 2 mm to achieve better polarization filtering effects. The proposed sensor is made of same size air holes which is easy to fabricate, cost effective, and shows better sensitivity and polarization filtering effects than several other sensors. It is expected that the sensor is suitable for wide RI detection range and capable of providing excellent polarization effect. The proposed sensor can be used for various applications including environmental detection, chemical sensing, biosensors, and pharmaceutical inspection.