Performance Analysis of Low Young's Modulus Material-Based Optical Fiber Pressure Sensor

Optical fiber sensors (OFSs) have numerous integrated benefits including being lightweight, immune to electromagnetic interference, highly sensitive, able to operate at high temperatures, resistant to corrosion, and having a wider bandwidth. In general, a high Young's modulus (YM) material (e.g. Si) is utilized to make the OFS for pressure monitoring. However, because of the risk of shattering the fiber sensors, these hard material (i.e., high YM) based OFS are not appropriate for body-integrated biomedical applications. This work focuses on the design and theoretical performance analysis of low YM and biocompatible materials-based pressure sensors for wearable applications. Two low YM materials, Polyurethane and Silicone elastomer-based pressure sensors are thoroughly investigated numerically using COMSOL Multiphysics. Two optical fiber structures, namely capillary optical fiber (COF) and anti-resonant (AR) structures with the mentioned low YM materials are investigated and compared the performance with conventional high YM materials (e.g. Si). In general, it is found that the confinement loss (in dB) of the proposed flexible pressure sensor increases linearly with the applied pressure. The highest sensitivity of the Polyurethane and Silicone elastomer-based pressure sensors are found to be 1.09 ×10
³
dB/GPa and 75.26 dB/GPa, respectively for COF structure. On the other hand, the conventional Silica material-based pressure sensor showed a sensitivity of only 6 ×10–
³
dB/GPa for the same design parameters. Thus, the sensitivity of the polyurethane material showed the highest sensitivity among the investigated materials due to its low YM and Poisson ratio (i.e. mechanical properties).