Enhanced 1.5 μm emission from Yb 3+ /Er 3+ codoped tungsten tellurite glasses for broadband near-infrared optical fiber amplifiers and tunable fiber lasers.

Strong 1.5 μm emission with full width at half maximum (FWHM) of 64 nm has been obtained in 3 mol% Yb 2 O 3 and 1 mol% Er 2 O 3 codoped tungsten tellurite glass under the excitation of a 980 nm laser diode. Spectroscopic properties of Yb 3+ /Er 3+ codoped tungsten tellurite glasses as a function of Yb 3+ and Er 3+ contents are systematically investigated by absorption spectra, emission spectra and lifetime measurement. The structure of tungsten tellurite glass is characterized by Raman spectrum. In addition, emission cross section and gain coefficient of Er 3+ ions near 1.5 μm are determined and respective maximum values attain 1.06 × 10 -20 cm 2 and 4.07 cm -1 . Moreover, gain bandwidth and figure of merit associated with gain properties in tungsten tellurite glass are calculated and compared with other reported glasses. These results indicate that Yb 3+ /Er 3+ codoped tungsten tellurite glasses with better gain properties are promising candidates in constructing broadband optical fiber amplifiers and tunable fiber lasers in the optical telecommunication window.