A calibration-free fiber sensor based on CdZnSe/ZnSe/ZnS quantum dots for real-time monitoring of human thermal activities

A calibration-free fiber sensor based on CdZnSe/ZnSe/ZnS quantum dots (QDs) was proposed. The sensor was fabricated by filling fully a thick hollow core fiber (HCF) with QDs solutions and fused tapering to seal the micro-cavity subsequently. Results showed that sensors with different cavity lengths can provide a similar temperature sensitivity of 0.12 nm/°C with an excellent linearity. Compared with sensors based on the interference and grating, the temperature demodulation function is universal due to a fact that fluorescence wavelengths changed by temperatures are only related to QDs materials, independent of the cavity length and the excitation power, so the sensor can be calibration-free, providing an idea and the technology for the calibration-free work of optical fiber temperature sensor in the future. Furthermore, the sensor exhibiting an excellent stability and repeatability can monitor thermal signals generated by human activity in real-time.