A curvature fiber optic sensor with expandable measurement points based on anti-resonant hollow-core optical fiber

Abstract

This work presents an expandable fiber optic curvature sensor. The sensor achieves multi-point curvature measurements by cascading different lengths of anti-resonant hollow-core fiber sensing units. The sensing unit is formed by connecting the anti-resonant hollow-core fiber between two single-mode fibers. The highest curvature sensitivity achieved by a single sensing unit is −11.86 nm/m−1, with a low temperature sensitivity of only 3 pm/°C. This sensing unit is readily manufacturable and exhibits good curvature sensitivity, temperature insensitivity, and stability. In contrast to traditional multi-point distributed sensors, this sensor can be flexibly installed at various positions, providing curvature sensing at desired locations. Moreover, it demonstrates the potential for multi-point curvature measurements, offering a promising solution for practical applications such as structural monitoring and robotic posture detection.