Comparative study between LPFG- and FBG-based bending sensors

A comparative study on behavior of grating-based bending sensors, which include long-period fiber grating (LPFG) and fiber Bragg grating (FBG), has been performed in this article. In order to simulate these grating-based bending sensors, a comprehensive simulation model has been presented. According to our simulation results, LPFG-based bending sensor on the standard SMF-28 optical fiber has bending sensitivity of 8.78 nm/m−1. The linear operation range for this bending sensor is between K=0 m−1 and K=5 m−1 (K is the amount of bending curvature). On the other hand, a FBG-based bending sensor on a single-mode 4-core fiber (4CF) has been studied. Our simulation results show that this bending sensor has bending sensitivity of 85.57 pm/m−1 and it has linear response over the entire considered range of bending, K=0-6 m−1. For full-rotation bend sensing, two adjacent cores of this optical fiber should be utilized.