Analysis of Fringe Visibility and Film Thickness Relationship of an Optical Fiber CO2 Sensor

The thickness of a Fabry-Perot interferometer (FPI) cavity plays a vital role controlling the intensity, absorbance, and fringe visibility of the FPI at a particular wavelength. In this work, an FPI-based optical fiber CO2 sensor (OFCS) was simulated for the film thickness range of 4.88-7.23 μm (achieved from a few scanning electron microscope images of an OFCS). The absorbance peak was achieved at a wavelength of 600 nm. The normalized intensity decreases by 86.7 %, absorbance increases by 35.1 %, and fringe visibility decreases by 3.31 % at around 600 nm for rising the film thickness from 4.88 μm to 7.23 μm, The difference between practical and simulated fringe visibility was monitored. So, the idea of the desired output can be achieved by simulating the mathematical model of an FPI-based optical fiber sensor before performing the lab experiments.