Design and simulation of photonic crystal fibre sensor for harmful chemicals detection in polycarbonate plastics

A photonic crystal fiber (PCF) sensor for detecting harmful chemicals such as di(2-ethylhexyl) phthalate (DEHP), bisphenol A (BPA), and bisphenol S (BPS) in polycarbonate plastics has been proposed using fused silica as the substrate, consisting of a decagonal core hole and 2 layers of circular cladding air holes arranged in a hexagonal pattern, and numerically analysed using COMSOL Multiphysics with the Finite Element Method. The PCF sensor was evaluated for the effective area, nonlinear coefficient, chromatic dispersion, V-parameter, power fraction, relative sensitivity, and confinement loss from the visible to infrared wavelength range. The results show relative sensitivities of 99.14%, 99.93%, and 99.95% for DEHP, BPA, and BPS, respectively, at an optimum wavelength of 0.4 µm, with confinement losses ranging from 10⁻²¹ to 10⁻¹⁷ dB/m for all the test analytes. The design was also shown to be robust against variations in cladding air hole layers and global dimensions, making it a promising candidate for practical sensing applications in the plastic production industry. Furthermore, the sensor’s ability to achieve low confinement losses, low chromatic dispersion, and a high nonlinear coefficient demonstrates its suitability for a range of other applications including optical communication, supercontinuum generation, and light illumination.