Highly reliable all-fiber temperature sensor based on the fluorescence intensity ratio (FIR) technique in Er3+/Yb3+ co-doped NaYF4 phosphors

A simple and feasible method was used to fabricate the optical temperature probe. A point all-fiber temperature sensor was built based on the up-conversion emission spectra of Er3+/Yb3+ co-doped NaYF4 phosphors.