Influence of ${\rm Ce}^{3+}$ Codoping on the Photoluminescence Excitation Channels of Phosphosilicate Yb/Er-Doped Glasses

The luminescence properties of the Yb/Er-doped phosphosilicate preforms used for the design of active optical fibers were investigated under a tunable laser excitation from ultraviolet to infrared domain. We demonstrated that codoping the glass matrix with Ce³⁺ ions strongly influences the infrared emission associated with Er³⁺ ions, it enhances the energy transfer from Yb³⁺ to Er³⁺ ions, and it provides an additional ultraviolet excitation channel for the emission of both Yb³⁺ and Er³⁺ ions. The excitation/emission pathways are discussed on the basis of models proposed in literature for other systems.