Detection of harmful food additives using highly sensitive photonic crystal fiber

This paper presents three different structures of index guided hexagonal shaped Hollow Core Photonic Crystal Fiber (HC-PCF) specially designed for sensing harmful food additives like Saccharin, Sorbitol and Butyl Acetate. The proposed PCFs have three distinct combinations of hexagonal and/or circular airholes at the innermost cladding layer and in the core region. A comparative study among the proposed structures reveals that the introduction of the hexagonal airholes at the innermost cladding layer increases the sensitivity. Also, the addition of the large circular airholes at the outermost layer reduces the confinement loss in all three structures. The diameters of the airholes of the innermost and outermost layer of the cladding region are gradually varied to optimize the PCFs. The numerical inquiry reveals that the optimized best structure shows relative sensitivity of 88.75%, 87.37% and 86.72% for Saccharin, Sorbitol, and Butyl Acetate respectively at the operating wavelength of 1.33 μm. The performances of the proposed structures are also investigated using Ethanol as the sensed sample for the purpose of comparison with previously reported works. The comparison shows that the introduced fibers outperform most of the recent works. Numerical analyses of the proposed structures are conducted using Full Vectorial Finite Element Method (FV-FEM).