A study on measuring refractive index by using an optoelectronic oscillator

Abstract

This paper presents a study on measuring the refractive index of liquids by using an optoelectronic oscillator. The measurement principle is based on a strong relation between the oscillation frequency and the global loop delay of the oscillator. Several experiments have been implemented to determine the refractive index of acetone, acetonitrile, 1,4-dioxane and 1,3-dioxolane. The experimental results are discussed and compared with previous publications. We also propose a new technique to monitor the refractive index of a liquid in real-time by using an external reference frequency source, a mixer and a frequency counter.