A Novel Highly Sensitive Photonic Crystal Fiber Sensor for Detecting PH Levels of Acetic Acid Aqueous Solution Based on Surface Plasmon Resonance

A novel PCF sensor based on surface plasmon resonance (SPR) to detect pH levels of Acetic acid aqueous solution is proposed in this paper. This proposed sensor has a sensing range for 1%-25% acetic acid aqueous solution (2.51-1.90 in pH level). Gold layer is used as plasmonic metal along with a TiO 2 layer for better plasmonic excitation and enhancing evanescent field. Analyte is passed through a rectangular channel in center and a channel surrounding the metal layer. For some analyte samples of refractive index(RI) ranging in between 1.33-1.37, we have investigated effective RI, relative sensitivity in x and y polarizations, confinement loss and effective area via Finite Element Method (FEM). As a result of proper optimization maximum wavelength sensitivity of 10,000 nm/RIU and wavelength resolution of $1\times 10^{-5}$ RIU is achieved at 1.3620 RI level which secures excessive detection reliability of minute RI changes. This sensor evinces moderated confinement loss which certifies simplicity in fabricating the design. Relation of confinement loss, relative sensitivity and effective area against wavelength show eminent indication of better sensing capability for various pH levels of acetic acid.