PDMS-based tactile sensing: distributed sensor with a multiple-core polymer waveguide

In this paper, we create a planar polymer optical waveguide sensor with four parallel cores. This four-core array features an optimized geometry obtained through a beam propagation method simulation. UV-curable polydimethyl siloxane is selected for the cladding, while a UV-curable acrylate resin is selected as the waveguide core. When pressure is applied to the core at different locations, precise sensing of the pressure value and location is achieved through changes in the output light intensity from the pressurized cores. The experimental results show that the sensitivities of four cores, Ch.1 to 4, in a fabricated waveguide sensor in a pressure range of 0-1.13 MPa, are 8.7 dB/MPa, 10.73 dB/MPa, 9.2 dB/MPa, and 10.88 dB/MPa, respectively. Additionally, we propose a 3D crossed core structure as a potential direction for future development. Optical waveguide structures not only demonstrate good flexibility and high sensitivity, but also have broad application potential, especially in the fields of flexible electronics and smart sensing.