Hollow-Core Fiber-Based Curvature Sensor with High Sensitivity and Large Dynamic Range

We study the application of a tubular-lattice hollow-core fiber displaying thin cladding tubes as a high-sensitivity and large-dynamic range curvature sensor. The device working principle is based on bending-induced core and cladding modes couplings occurring at specific wavelengths and at specific curvature radii. Our characterizations allowed us to determine a sensitivity of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$(\mathbf{29.3} \pm \mathbf{0.4})\ \mathbf{nm}/\mathbf{m}^{-1}$</tex> for a curvature variation range of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathbf{17}\ \mathbf{m}^{-\mathbf{1}}$</tex>. These figures are high when compared with other curvature sensors based on different optical fiber-based sensing configurations. We understand that our work provides a valid path for achieving new hollow-core curvature sensors with enhanced sensitivity and large dynamic range.