Polymer Waveguide-Based Optical Tactile Sensor Fabricated by the Mosquito Method

In this article, optical waveguides are designed for ultrasensitive tactile sensing with fast response and high sensitivity. We create a polymer-based optical waveguide sensor that has been innovatively developed to address the limitations of conventional optical fiber-based sensors, particularly their flexibility and tactile capabilities. The principle of the sensor is output light intensity variation due to core bending. Our optical waveguides consist of polydimethylsiloxane (PDMS) as the cladding. An acrylate resin (XCL-02) is used for the core by dispensing its monomer into the PDMS (cladding) monomer using the Mosquito method. We demonstrate that there is a nearly linear relationship between the extra pressure and the insertion loss of the waveguide. The PDMS-based sensor exhibits high repeatability in the measurement pressure range. The sensor shows a sensitivity of 9.12 dB/MPa and a measurement range of 0–2.3 MPa, with a core diameter of approximately 100 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu $ </tex-math></inline-formula>m and a light wavelength of 850 nm. This investigation sheds light on crucial factors influencing the sensor’s performance and response to the applied forces. We believe that this sensor can be applied in various fields, such as medical applications, wearable devices, and robotic tactile systems.