Optical Properties in Refractive Index Liquids Using a Tapered Optical Fiber Sensor: A Combined Simulation and Experimental Approach

The advantages of optical fibers that are immune to electromagnetic waves, high sensitivity, resistance to temperature and pressure, and resistant to corrosions, broaden the reach of this field, especially after the pandemic era. One of the sensor designs that can be explored is the tapered optical fiber sensor because of its advantages of being more sensitive, easy to develop, wider applications and having a larger contact surface between the optical fiber and the surrounding conditions. In this study, research on tapered fiber optic sensors through simulation and experiment was done to detect five refractive index readings using different refractive index liquids. The main objective of this study is to analyze the absorption readings of refractive index liquids through simulation and experiment. The simulation of the tapered fiber optic sensor was executed using COMSOL MULTIPHYSICS 6.0 software. An experimental study was made using a Deuterium Tungsten Halogen light source and a FLAME spectrometer. A total of five refractive indices were used namely 1.46, 1.50, 1.54, 1.58 and 1.62. While a total of 6 wavelengths has been selected, namely 365 nm, 406 nm, 473 nm, 532 nm, 589 nm and 632 nm. The results of the sensitivity and limit of detection analysis of tapered optical fiber sensors through simulation and experiment methods exhibited similar pattern. Despite a minor difference in the sensitivity value data, the simulation results can still predict the optical properties of the refractive index liquid because the data difference is too small, which is only between 0.69% to 5.91%.