Role of CaO addition in the local order around Erbium in SiO2–GeO2–P2O5 fiber preforms

The development of materials for optical signal processing represents a major issue in present technology. In this contribution we present a study on Er-doped fiber preforms where particular attention is devoted on how the addition of CaO in the glass modifies the local environment of the rare earth. The results from photoluminescence and Extended X-ray Absorption Fine Structure (EXAFS) are compared and a clear link between the width of the emission line at 1.5 μm and the amorphous/crystalline local structure around the Er3+ ion is evidenced.