Study of Surface Plasmon Resonance Sensor Based on Polymer-Tipped Optical Fiber With Barium Titanate Layer

In this article, an optical fiber SPR sensor based on polymer-tipped optical fiber (PTOF) coated with a gold film and a Barium Titanate (BaTiO ₃ ) layer has been designed and optimized by finite difference time-domain (FDTD) method. Three SPR dips are observed and the optimal sensitivity of single-mode PTOF SPR sensor coated with an additional BaTiO ₃ layer reaches 6710 nm/RIU when refractive index (RI) of analyte is 1.333-1.343. A novel measurement method based on sum-value and difference-value of two SPR dips is proposed. Compared with conventional measurement method based on single dip, the measurement based on sum-value can significantly improve the sensitivity and the measurement based on difference-value can effectively reduce the environmental influence.