Near-IR Luminescence of Rare-Earth Ions (Er(3+), Pr(3+), Ho(3+), Tm(3+)) in Titanate–Germanate Glasses under Excitation of Yb(3+)

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(2)-modified germanate glasses co-doped with Yb(3+)/Ln(3+) (Ln = Pr, Er, Tm, Ho) with excellent spectroscopic properties. Glass systems were directly excited at 980 nm (the (2)F(7/2) → (2)F(5/2) transition of Yb(3+)). We demonstrated that the introduction of TiO(2) is a promising option to significantly enhance the main near-infrared luminescence bands located at the optical telecommunication window at 1.3 μm (Pr(3+): (1)G(4) → (3)H(5)), 1.5 μm (Er(3+): (4)I(13/2) → (4)I(15/2)), 1.8 μm (Tm(3+): (3)F(4) → (3)H(6)) and 2.0 μm (Ho(3+): (5)I(7) → (7)I(8)). Based on the lifetime values, the energy transfer efficiencies (η(ET)) were estimated. The values of η(ET) are changed from 31% for Yb(3+)/Ho(3+) glass to nearly 53% for Yb(3+)/Pr(3+) 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.