The plasma resonance fiber optic sensor has a research values in theory and is widely used in engineering because of its simple structure and high sensitivity. It is a simple and sensitive method to measure the refractive index with optical fiber plasma wave. We make use of this characteristic to manufacture the plasma resonance fiber optic sensor which can detect the cure of epoxy compo site. We study the method of testing the solutions which have different refractive index with plasma resonance fiber optic sensor. A fiber optic sensing probe which has reliable performance and convenient operation for detecting the refractive index has been designed. The system for detecting the solution refractive index is developed and used to measure the refractive index of epoxy during the different phases in the cure process. Result shows that this system is credible and stable, the parameters tested are in accord with the facts.
