Optical and structural properties of (70−x−y)TeO₂-20WO₃-10Y₂O₃-xEr2O3-yYb₂O₃ glasses

Highlights: • Er³⁺ and Yb³⁺ doped heavy metal oxide tellurite glasses were prepared. • Prepared glasses can be used for optical amplifiers and spectral conversion. • FWHM of 1.54 μm emission of Er³⁺ is found to be about 100 nm. - Abstract: TeO₂ based glasses with molar composition (70−x−y)TeO₂-20WO₃-10Y₂O₃-xEr₂O₃-yYb₂O₃, where x = 0 and 0.5 mol% and y = 0, 0.5, 1, 2 and 4 mol%, were prepared by the melt quenching technique. At room temperature, all the samples are transparent, mechanical and thermally stable. This vitreous system was found to be promising for potential applications in optical amplification, in particular in erbium doped fiber amplifiers (EDFA), Raman optical amplifiers and also in spectral conversion for applications in photovoltaic technology. The Raman spectrum of the base glass (Er0Yb0), using laser excitation of 532 nm, showed vibrational bands related to Te−O and W−O bonds. The introduction of WO₃ results in a higher bandwidth relatively to SiO₂ based glasses and even other TeO₂ based glasses, making this vitreous system promising for Raman optical amplification. With regard to the optical analysis, an increase of the intensity of the upconversion emission with the increase of the content of the sensitizer ions Yb³⁺ was observed. The Er³⁺ emission around 1540 nm has a full width at half maximum of about 100 nm in the temperature range of 70–300 K, which is a very interesting value relatively to those reported for other glassy systems, considering optical amplification as a potential application