A highly sensitive temperature sensor with a PDMS-coated tapered dispersion compensation fiber structure

A highly sensitive optical fiber temperature sensor with a polydimethylsiloxane (PDMS)- coated tapered dispersion compensation fiber (DCF) structure is proposed, the structure consists of single mode fiber (SMF)- tapered dispersion compensation-single mode fiber (STDS). The sensing principle is based on the interference between DCF and SMF due to a large core diameter mismatch. The interference of this composite structure is easily affected by the surrounding refractive index (SRI), which ultimately results in a change in the interference dip of the transmission spectrum. Thermosensitive PDMS is covers the tapered dispersion compensation region, which can increase the sensitivity of the temperature sensor, protect the microstructure, and improve the reliability of the structure in practical application. Experiment temperature results verified that the maximum temperature sensitivity of the sensor was 0.22 nm/degrees C in a range of 20 degrees C-100 degrees C, with good repeatability in this range. Compared with the original fiber sensors and PDMS-coated fibers, the temperature sensitivity increased by 5.2 times and 2.24 times, respectively. This sensor can be realistically applied to biochemical sensing and industrial structural health detection fields due to its compact structure, high sensitivity, and simple processing.