Optical fiber bending sensor based on speckle pattern imaging

In this paper, we propose a new fiber bending sensor based on speckle pattern imaging. The design and implementation of the sensor are demonstrated by simulated studies. The speckle pattern imaging technique by using a multimode fiber can offer high spatial resolution. In this study, we showed that the bending sensor responds very sensitively by using the correlation of the images. The fiber sensing part consists of a curve in a form similar to the S structure. We reached a sensitivity of 0.0295 μm-1 by bending the fiber only 60°. Sensitivity can be further increased by reducing the bending diameter or creating a full loop.