Experimental research of optical fiber sensor for salinity measurement

Plastic optic fiber sensor is proposed and experimentally investigated for salinity measurement based on light power determination in different concentration of sodium chloride (NaCl) solution. U-shaped and spiral-shaped plastic optical fibers were used as sensor heads and light transmitting elements. As the NaCl concentration varies from 0% to 35%, the output transmitted light power of the sensor is proportional to salinity concentration. The sensitivities of the U-shaped sensor head and the spiral-shaped sensor head reach 0.42 mV/% and 0.13 mV/%, respectively. The experimental results indicate that the POF sensor has characteristics of feasibility, reversibility and stability.