Four-beam single fiber optic interferometer and its sensing characteristics

A multi-parameters measurement technique that uses a four-core fiber as the sensing element has been proposed and demonstrated. The four-core fiber act as a four-beam interferometer in which phase differences is a function of curvature, twisting angle, and the variation of temperature in the plane containing the cores results in the shift of the far-field interferometric grid pattern. The relationship between the far-field grid pattern shift and the multi-parameters has been established and the experimental results were also confirmed this.