INTERNATIONAL CONFERENCE ON MATHEMATICS – ENGINEERING – NATURAL & MEDICAL SCIENCES , Al Karak, Jordan, 30 - 31 January 2021, pp.502-503
In this study, U-shaped bending fiber optic sensor tips based on bending losses and sensitivity to the medium’s refractive index changes were designed and produced. U-1, U-2, and U-3 sensing tips were produced by using bare polymer fibers with three different fiber diameters of 1, 2, and 3 mm, respectively. Since all the fibers have a high numerical aperture value of 0.5, this situation facilitates the light’s guiding into the fiber easily. Tips’ responses during the transition between air and water were considered and obtained sensitivity degrees. Three sensor tips were used to measure ethanol-water and methanol-water mixtures. The tip named U-2 was found to be most suitable for the detection of ethanol concentration. This sensor tip was able to detect the change in the refractive index of Δn<5×10-4 RIU with the linearity of 0,999 in ethanol concentrations. Similarly, the sensor tip named U-3 was the most appropriate tip for the detection of methanol concentration. This sensor tip was able to detect the difference in the refractive index of Δn<2×10-4 RIU with the linearity of 0,997. Both sensor tips were able to detect with high precision, stability, and repeatability up to 15% alcohol concentration in the mixtures. Besides, the sensors produced very simple, easy, and cheap can be benefited to recognize alcohol type in water.