Wide Range FBG Displacement Sensor Based on Twin-Core Fiber Filter

In this paper, we present a wide range displacement sensor system using the fiber Bragg grating (FBG), spring, and a twin-core fiber. The quantitative analysis of the theory of the cascaded FBG-spring system for displacement measurement is introduced together with the basic working principle of a twin-core fiber filter. The feasibility of the method is demonstrated in experiments which shows the output optical intensity linear relation with the displacement. The characteristics of the wide range, high resolution, low cost, and compact scheme would make this method more applicable.