Twin-core fiber white light interferometric bending sensor

A fiber optic bending sensing system that uses twin-core fiber as the sensing element has been proposed and demonstrated. The twin-core fiber act as a two-beam interferometer in which phase differences is a function of the curvature, and it can be demodulated by the shift of the unique identification spectrum. By way of FFT analysis of the white light interferometric spectrum, the variation of bending can be measured. The relationship between the bending curvature and the shift of the unique identification spectrum has been given and the experimental results were also confirmed this.