Optical Fiber Sensor for Measuring Refractive Index

TLDR: In this paper, an optical fiber sensor for measuring a liquid refractive index is proposed, which is made of a plastic fiber and tested with lamp oil and light oil as specimens, and a measurement accuracy of nm to the third decimal place is obtained.

Abstract: An optical fiber sensor for measuring a liquid refractive index is proposed. When an optical fiber is bent and part of its cladding is stripped off, the light energy (E) emerging from the fiber depends on the refractive index of the surrounding medium (nm). The change in nm can be found from E. The light output energy and the measuring sensitivity are calculated numerically as a function of nm for several values of the bending radius R. The fundamental characteristics of the sensor, made of a plastic fiber, are investigated using lamp oil and light oil as specimens, and a measurement accuracy of nm to the third decimal place is easily obtained. As applications of this sensor, measurement of liquid density and detection of oil are described.