Design of a low cost and high sensitivity sensor for curve measurement

In the dual-core optical fiber, the two beams are launched into two cores simultaneously, the solution of coupled mode equations is derived. It is shown that the slight change of the refractive index can affect the coupling between the cores, which causes the change of power of two cores. Based on this idea, the low-cost, high-sensitivity curve sensor based on the dual-core optical fiber is proposed. Numerical simulations with a full vectorial beam propagation method demonstrate that it allows highly accurate curve angle detection. The sensitivity of the curve sensor can reach 1.1405 mW/deg. Moreover, by optimizing the pitch and choosing the different propagation direction and the output power of light source, we can obtain the higher sensitivity.