Near-IR Luminescence of Rare-Earth Ions (Er, Pr, Ho, Tm) in Titanate-Germanate Glasses under Excitation of Yb.

Inorganic glasses co-doped with rare-earth ions have a key potential application value in the field of optical communications. In this paper, we have fabricated and then characterized multicomponent TiO-modified germanate glasses co-doped with Yb/Ln (Ln = Pr, Er, Tm, Ho) with excellent spectroscopic properties. Glass systems were directly excited at 980 nm (the F → F transition of Yb). We demonstrated that the introduction of TiO is a promising option to significantly enhance the main near-infrared luminescence bands located at the optical telecommunication window at 1.3 μm (Pr: G → H), 1.5 μm (Er: I → I), 1.8 μm (Tm: F → H) and 2.0 μm (Ho: I → I). Based on the lifetime values, the energy transfer efficiencies (η) were estimated. The values of η are changed from 31% for Yb/Ho glass to nearly 53% for Yb/Pr glass. The investigations show that obtained titanate-germanate glass is an interesting type of special glasses integrating luminescence properties and spectroscopic parameters, which may be a promising candidate for application in laser sources emitting radiation and broadband tunable amplifiers operating in the near-infrared range.