Spectroscopic properties and energy transfer of Tm3+/Ho3+-codoped TeO2–WO3–ZnO glasses for 1.47 μm amplifier

We report on spectroscopic properties and energy transfer of Tm3+/Ho3+-codoped tungsten tellurite glasses for 1.47 μm amplifier. Fluorescence spectra and the analysis of energy transfer indicate that Ho3+ is an excellent codopant for 1.47 μm emission. Comparing with other tellurite glasses, the radiative lifetime of the 3H4 level of Tm3+ in tungsten tellurite glass is slightly lower, but the spontaneous emission probability, stimulated emission cross-section and the figure of merit for bandwidth are obviously larger. Although the pump efficiency of tungsten tellurite amplifier is ∼50% less than that of fluoride glass, the figure of merit for bandwidth is approximately three times larger in tungsten tellurite glass than in fluoride glass. The results indicate that Tm3+/Ho3+-codoped tungsten tellurite glass is attractive for broadband amplifier.