Highly sensitive strain, magnetic field, and temperature sensor using PDMS and a Fabry-Perot interferometer

In this paper, a high-sensitivity fiber optic sensor, consisting of a Fabry-Perot interferometer (FPI) based on polydimethylsiloxane (PDMS) and a capillary, is presented. The FPI structure shows excellent sensing performance in strain measurement with a sensitivity of ∼ 0.221 nm/µε and a linearity of 0.999 within the range from 0 µε to 266 µε. The FPI was pasted onto Terfenol-D for magnetic field sensing, and the sensor shows the sensitivity of ∼ 1.84 nm/mT with linearity of 0.997 in the range of 14-46 mT. The consistency of multiple experimental results demonstrates the repeatability and reliability of the sensor. When the magnetic field is 18 mT and 22 mT, the magnetic field direction sensitivity of the sensor reaches ∼ 0.33 nm/° and ∼ 0.50 nm/°, respectively. The sensor also shows high temperature sensitivity of ∼ 1.82 nm/°C and good linearity. The sensor has the advantages of easy manufacturing, low cost, high sensitivity, and excellent linearity. This versatile sensor is suitable for measurements in power equipment monitoring, medical wearable devices, and intelligent robots, providing a solution for physical quantity monitoring.