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.