Er3+/Yb3+ co-doped tellurite glasses for optical fiber thermometry upon UV and NIR excitations

Tellurite glasses of TeO2-BaF2- REF3 (RE = La, Gd, and Y) co-doped with Er3+/Yb3+ were prepared and investigated comparatively for optical fiber temperature sensors. For this purpose, their thermal and optical properties were examined in detail. The J-O theory was adopted to estimate the transition properties based on absorption spectra. The dominant green emissions were observed in both of the downshifting and upconversion luminescence. The optical temperature sensing abilities based on the FIR of Er3+ green emissions were studied under both of the UV (380 nm) and NIR (980 nm) excitations. Results show that these three tellurite glasses, especially for the TBG glass, should be very qualified for the design of optical fiber temperature sensors under different excitation modes.