Preparation and optical properties of Er³⁺-doped gadolinium borosilicate glasses

Er³⁺-doped Gd₂O₃-SiO₂ -B₂O₃-Na₂O glasses were prepared, and formation range of glass of Gd₂O₃-SiO₂ -B₂O₃ system was experimentally obtained. It is found that the glass phase can be formed only when the content of SiO₂ is 0-50% (molar fraction), Gd₂O₃ is 0-30% (molar fraction) and B₂O₃ is above 20% (molar fraction) in this glass system. The glass can also be obtained but becomes translucent at the contents of 60% (molar fraction) SiO₂ and 30% Gd₂O₃, or at the contents of 60% (molar fraction) SiO₂ and 30% (molar fraction) B₂O₃. There is no glass phase formed in other glass components. Glass forming ability for Gd₂O₃ content of 10%, was characterized by the value of β, the parameter of crystallization tendency, which is 0.32-1.76, obtained from the differential thermal analysis. The absorption and emission cross section, the J-O parameters Ωt_{(2, 4, 6)} and radiative transition probabilities were calculated by using the theory of McCumber and Judd-Ofelt. The emission properties at 1.5 μm of the samples are discussed with the product of full width at half maximum and stimulated emission cross section. It can be seen that the value of the FWHM × σ_e^peak product in the prepared glass is more than those of germanate, silicate and phosphate glasses. Furthermore, the maximum value of the product among these glasses reported in this work is close to that of oxyfluoride silicate glass. Therefore, the Er³⁺-doped gadolinium borosilicate glass in this paper is a candidate for broadband erbium doped fiber amplifiers.