Optical Fiber Sensor for Measuring Refractive Index

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 (n m). The change in n m can be found from E. The light output energy and the measuring sensitivity are calculated numerically as a function of n m 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 n m to the third decimal place is easily obtained. As applications of this sensor, measurement of liquid density and detection of oil are described.

Concentration measurement of refrigerant/refrigeration oil mixture by refractive index

“…One is to detect a change of light intensity through a sensor [17,18], the second is to detect a change of optical path [15,19,20] and the third is to detect the critical angle [11,16,21]. The purpose of this study is to provide fundamental data which is useful in the development of the sensor.…”

Effects of immersion duration and temperature on mechanical properties of optical fibers aged in CTAC aqueous solution

“…Based on the measurement of evanescence wave adsorption [5,7,14,17,23,28,29], optical fiber sensors are increasingly used. There is a growing interest in this method due to the fact that there is fast implantation of optical fiber probes, which are adapted for in situ measurements, and there is no need of a reference electrode or several samples [7].…”

Automatic device for continuous measurement of potential distribution and acid stratification in flooded lead-acid batteries

“…Other in situ measurement principles are based e.g. on measuring the refractive index by using optical fibres [7,8]. The method presented in this article by using micro reference cells is applicable for in situ measurements as well.…”