A Study on Core Diameter Variations and Their Impact on FBG Sensor Performance

In this paper, the investigations of various impacts of different core diameters, from <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$2 \mu \mathrm{m}$</tex> to <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$60 \mu \mathrm{m}$</tex>, on the performance of Fiber Bragg Grating (FBG) sensors is done using Opti Grating simulations with a fixed cladding diameter of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$125 \mu \mathrm{m}$</tex>. Sensor sensitivity for each core width is examined under thermal, strain, index difference, and no perturbation conditions. For greater sensitivity, smaller core widths and maximum wavelength shifts are preferred in FBG sensor fabrication, as these factors contribute significantly to precise measurements. Key metrics like Bragg wavelength shift, reflectivity, and transmittivity are analysed to identify the ideal core size for high-precision FBG applications. These findings offer guidelines for optimizing core dimensions to enhance efficiency, adaptability, and stability, which support core size selection across various sensing applications based on operational needs.