Dy3+ doped Ge-Ga-Sb-Se glasses and optical fibers for the mid-IR gain media

Dy3+-doped selenide glasses and their optical fibers in the Ge-Ga-Sb-Se glass-forming system were fabricated and their mid infrared (MIR) emission (2.5-5 μm) characteristics were analyzed. Optimum concentration for 3 μm emission band was determined as 0.02 mol% due to cross relaxation between Dy3+ ions. Sensitizers such as Pr3+, Ho3+, Tb3+ or Tm3+ ions were co-doped to improve MIR emissions from Dy3+. Pr3+ provided the highest emission intensity of Dy3+:6H13/2 → 6H15/2 but suffered from the efficient energy transfer between two ions involved. Tm3+ showed further enhancement due to its co-excitation wavelength of 1.8 μm.