A threaded curvature-controlled optical fiber for large transient displacement sensing

Utilizing the mechanism of macrobending loss, we designed a multiple-arc optical fiber sensor capable of measuring large transient displacements with high accuracy. Multiple arcs, with curvatures that can be controlled to amplify the bending loss, are formed by threading a fiber onto a soft, narrow plate. Specifically, we transfer the complicated control of fiber curvatures to the control of a much simpler linear deformation. To demonstrate its capability of measuring transient displacements of flexible structures, the vibration of a cantilever beam was measured. Both the experimental and simulation results demonstrate that it can achieve a sensitivity of 5.96 V/mm and effectively capture details of transient vibrations. The proposed threaded optical fiber sensor, characterized by its simple manufacturing process, is suitable for diverse working environments requiring large dynamic displacement sensing. In addition, our work provides a method for amplifying the bending loss in a controllable way.