Unsafe food additive sensing through octagonal-core photonic crystal fibre sensor

Abstract

To detect food additives, a simple photonic crystal fibre design based on an octagonal hole and hollow circular cladding holes in two layers has been introduced. The numerical study of the design is conducted by simulation in the COMSOL Multiphysics software with the infiltrated test analytes: saccharin, sorbitol, and butyl acetate, operating in the wavelength variation from 1.6 to 4.0 µm. The performance of the proposed sensor is determined by analysing the principal optical parameters: effective refractive index, power fraction, relative sensitivity, confinement loss, chromatic dispersion, propagation constant, V-parameter, spot size, and beam divergence. At the optimal wavelength of 2.0 µm, the sensor design depicts high relative sensitivities of 98.06% for saccharin, 97.05% for sorbitol, 95.81% for butyl acetate, and 3.82 × 10−23 dB/m for saccharin, 3.44 × 10−22 dB/m for sorbitol, and 1.81 × 10−21 dB/m for butyl acetate for confinement loss, which is extremely low. Hence, the proposed food additive sensor is suitable for actual sensing applications based on these obtained results.