Temperature Dependence of Absorption and Energy Transfer Efficiency of Er/Yb/P Co-Doped Silica Fiber Core Glasses.

A high phosphorus Er/Yb co-doped silica (EYPS) fiber core glass was prepared using the sol-gel method combined with high-temperature sintering. The absorption spectra, emission spectra, and fluorescence decay curves were measured and compared in temperatures ranging from 300 to 480 K. Compared to 915 and 97x nm, the absorption cross-section at 940 nm (0.173 pm) demonstrates a weaker temperature dependence. Hence, the 940 nm pump mechanism is favorable for achieving a high-power laser output at 1.5 μm. Additionally, the double-exponential fluorescence decay of Yb ions and the emission intensity ratio of I/I were measured to evaluate the energy transfer efficiency from Yb ions to Er ions. Through the external heating and active quantum defect heating methods, the emission intensity ratios of I/I increase by 30.6% and 709.1%, respectively, from ~300 to ~480 K. The results indicate that the temperature rises significantly reduce the efficiency of the energy transfer from the Yb to the Er ions.