Polymer optical Bend Sensor based on eccentric Fiber Bragg Gratings for 3D Shape Detection

We report on 3D bending detection via polymer optical fibers with eccentric Bragg-gratings. The concept relies on simple inscription of Bragg gratings in graded-index multimode polymer optical fibers with the phase mask method. When bending the flexible fibers, the lattice constant is varied and the Bragg peak changes. Bending is calculated from these shifts and the associated intensity change. Thus, the inscription of multiple gratings from three different angles at one position along the fibers allows the detection of bending and shape in 3D. In the next step, the sensor will be applied for movement detection of the human hand by integrating the functionalized polymer optical fibers into a sensor glove to monitor the bending of joints. This represents an interesting alternative to fiber optical sensors, as the polymer fibers are more cost-efficient and flexible compared to their glass-based counterparts. Further application for the detection of strain, temperature, humidity or concentration will be explored, potentially also in multiplexed settings.