Flexible Polymer Shape Sensor Based on Planar Waveguide Bragg Gratings

A newly developed concept for a miniaturized optical shape sensor is demonstrated. The sensor consists of a flexible polymer bending beam with two integrated optical waveguide Bragg gratings spatially staggered to each other. We report on the basic layout and the fabrication process and characterize the fundamental sensing response by an elaborate testing scheme. The polymer shape sensor reveals a pronounced spectral shift of the Bragg wavelength of several nanometers upon deformation with a distinct directionality. In conjunction with an undiscernible hysteresis, these results highlight the general applicability of the polymer Bragg grating-based bending beam as a shape sensor.