Sensitivity Enhancement of Apodized Fiber Bragg Grating for Temperature Measurement

An apodized Fiber Bragg Grating (FBG) is designed to obtain minimal quantity of side lobes on the reflection spectrum for effective estimation of temperature sensitivity. Bare FBG cannot be implemented as a suitable option for sensing of temperature in a complex environment because it is composed of silica, which has a very low thermal expansion coefficient. Different kinds of materials having thermal expansion coefficients higher than silica are coated on designed apodized FBG to improve the sensitivity of temperature for the FBG. In this simulation work, titanium, nickel, gold, copper, silver, aluminum, lead, indium, polycarbonate, PMMA, and polyamide are coated on the apodized FBG to estimate the enhanced sensitivity for the temperature range of 25 to 75°C. The simulation results illustrated that the sensitivity of temperature for polyamide-coated FBG is highest than other coating materials.