Integrated multi-mode glass ceramic fiber for high-resolution temperature sensing

Optical temperature sensors, which can accurately detect temperature in biological systems, are crucial to the development of healthcare monitoring. To challenge the state-of-art technology, it is necessary to design single luminescence center doped materials with multi-wavelength emission for optical temperature sensors with more modes and higher resolution. Here, an Er³⁺ single-doped KYF₄ nanocrystals glass ceramic with an obvious thermochromic phenomenon is reported for the first time, which shows a different temperature-dependent green, red, and near-infrared luminescence behavior based on thermal disturbance model. In addition, Er³⁺ single-doped GC fiber was drawn and fabricated into multi-mode optical fiber temperature sensor, which has superior measured temperature resolution (＜0.5 ​°C), excellent detection limit (0.077 ​°C), and high correlation coefficient (R²) of 0.99997. More importantly, this sensor can monitor temperature in different scenarios with great environmental interference resistance and repeatability. These results indicate that our sensor shows great promise as a technology for environmental and healthcare monitoring, and it provides a route for the design of optical fiber temperature sensors with multi-mode and high resolution.