Influence of 4f absorption transitions of Dy3+ on the emission spectra of Tm3+-doped tellurite glasses

We have demonstrated that a fluorescence emission centered at ∼810 nm responsible for Tm3+:3H4→3H6 transition is effectively captured via re-absorption by an absorption transition corresponding to Dy3+:6H15/2→6F7/2 in tellurite glasses. It is known that Tm3+-doped fiber amplifiers operating at the 1450 nm band suffer from amplified spontaneous emission (ASE) at around 810 nm. Therefore, our experimental results imply that a Dy3+-doped layer introduced in the vicinity of the Tm3+-doped layer in an optical fiber, as a representative example, can efficiently absorb the ∼810 nm emission from thulium and consequently reduce the ASE power.