PDMS-based flexible distributed tactile sensor in a multi-waveguide system fabricated by the Mosquito Method

In this paper, a waveguide type optical tactile sensor for pressure distribution sensing is developed. The sensor consists of an array of four-core planar polymer waveguide which applies an optimized wiring pattern obtained through beam propagation method (BPM) simulation. UV curable poly dimethyl siloxane (PDMS) is employed as the cladding by feeding the monomers A and B with a ratio of 5:1 to control the mechanical flexibility. When pressure is applied at different locations on the waveguide, the amount and location of applied pressure can be precisely sensed by incremental insertion loss at each end of the different channels. Main principle for accurate sensing of this sensor is the bending losses in the various channels in the waveguide, which are highly sensitive to pressure-induced bending. The experimental results show that the sensitivities of 4 channels in a fabricated sensor are 8.7 dB/MPa, 10.73 dB/MPa, 9.2 dB/MPa and 10.88 dB/MPa, respectively in a range of 0-1.13 MPa.