Two-Dimensional Bending Vector Sensor Based on the Multimode-3-Core-Multimode Fiber Structure

A two-dimensional bending vector sensor based on the multimode-3-core-multimode fiber structure is proposed. The three cores of the 3-core fiber (3CF) distribute in an isosceles triangle. In order to obtain a higher bending sensitivity, two larger diameter external cores are selected in the design of the 3CF. Owing to the asymmetric structure of the 3CF, this sensor can distinguish multiple bending directions. In addition, the linear spectral response for bending and temperature is observed experimentally. The proposed sensor has many advantages. For example, it is compact, inexpensive, and easy to be fabricated. These characteristics of the sensor make it very attractive for two-dimensional bending sensing application.