Surface Curvature Sensor Based on Intracavity Sensing of Fiber Ring Laser

The measurement of surface curvature is of great significance in aerospace, structural health monitoring, energy batteries, etc. In this paper, a fiber-optic surface curvature sensor, based on intracavity sensing of fiber ring laser (FRL), is experimentally demonstrated. A no-core fiber- based filter performs as the sensing head of the FRL sensor. The response between the curvature of the NCF and the output wavelength of the FRL was investigated. In the measurement of curvature, the sensor system showed a narrow 3-dB bandwidth of 0.08 nm, with a high signal-to-noise ratio of about 60 dB. The curvature sensitivities were measured as −0.348 nm/m−1 within 0.2 m−1, and −3.185 nm/m−1 from 0.2 m−1 to 0.475 m−1. The performance of the surface curvature sensor was characterized by parameters, including output stability, temperature cross-sensitivity, and detection limit