Optical fiber temperature sensor based on the upconversion fluorescence intensity ratio of NaYF4:Er3+ excited by a 1525-nm laser

Remote and accurate temperature measurements in severe environments are of great importance. A 1525-nm wavelength located in the C band of optical fiber communication is used as a pumping light source for NaYF4:Er3+ phosphor possessing high upconversion efficiency. The upconversion luminescence characteristics were demonstrated in the temperature range of 160-400 K. Based on the thermal coupling energy level theory, the temperature measurement principle of the fluorescence intensity ratio is analyzed. The energy gap between the H-2(11/2) and (4)S(3/2 )energy levels of the Er3+ ions is approximately 787 cm(-1), which is appropriate for a temperature sensor. The experimental results indicated that its maximum temperature sensitivity was 0.00335 K-1. The proposed optical fiber temperature sensor indicates good hysteresis and repeatability and has potential applications in resisting electromagnetic interference and remote temperature sensing. (C) 2021 Optical Society of America

Automated summary

Remote and accurate temperature measurements in severe environments are crucial. In this study, a 1525-nm wavelength in the C band of optical fiber communication was utilized as a pumping light source for NaYF4:Er3+ phosphor with high upconversion efficiency. The temperature measurement principle of fluorescence intensity ratio was analyzed based on the thermal coupling energy level theory. The experimental results showed that the proposed optical fiber temperature sensor exhibited good hysteresis and repeatability, making it suitable for resisting electromagnetic interference and remote temperature sensing.