Curvature sensor based on an LPG written in an air-clad thin-core fiber

In this paper, we report a curvature sensor based on an LPG written in an air-clad thin-core fiber (AC-TCF). The achieved curvature sensitivity is -0.226 nm/m^-1 with a good linearity with R² value of 0.991. Unlike conventional LPGs, this AC-TCF LPG is insensitive to the variation of surrounding refractive index, due to the existence of the one ring of large air-holes in the cross section of the AC-TCF.