Comparative study of solution concentration variations for polymer optical fibers sensor

Abstract

In this paper, we report a comparative study of fiber optic sensors for the application of aqueous solutions concentration monitoring. A simple, economical, and efficient set-up for liquid concentration measurement system was developed using polymer optical fibers (POFs). Cornstarch, sucrose, and salt solutions with different concentrations were tested, and the output power and the refractive index obtained were compared. The sensitivity of the sensor is found ranging from 0.938 μW/ RIU to 96.9 μW/RIU in term of refractive index change and 0.04298 μW/molL-1 to 0.097 μW/molL-1 in terms of concentration. It has been found that the concentration is proportionally related to its refractive index where high refractive index will experience greater loss since the light rays tend to be refracted out of the fiber instead of being internally reflected. The experimental results also show that as the solution's concentration increases, the output power decreases.