OPTICAL-PROPERTIES OF DYSPROSIUM-DOPED LOW-PHONON-ENERGY GLASSES FOR A POTENTIAL 1.3-MU-M OPTICAL AMPLIFIER

Dysprosium-doped glasses were prepared in the system of gallium-based sulfide, tellurite, zirconium-based and indium-based fluorides and their optical properties mere studied, From the absorption cross sections of five f-f bands, three Judd-Ofelt parameters, Omega(t) (t = 2, 4, 6), of Dy3+ ion were determined, The compositional variation of the Omega(2) value showed the order sulfide > tellurite > fluorozirconate > fluoroindate, whereas the Omega(6) value showed the opposite tendency, Compositional variation of the fluorescence intensity ratio of the (F-4(9/2) --> H-6(13/2))/(F-4(9/2) --> H-6(15/2)) is explained by the ratio of Omega(2)/Omega(6) of doped Dy3+. The emission probabilities A and the branching ratio beta from H-6(9/2) and F-6(11/2) levels, which are the doublet initial level of the 1.3 mu m luminescence, mere calculated for the glasses, and it was found that both values showed a tendency similar to that of Omega(2) against the glass composition. In the sulfide glass, A was 2.6 x 10(3) s(-1) and beta mas 93%, both the highest in all of the glasses investigated, By 1.06 mu m pumping of a Nd:YAG laser, the sulfide glass showed strong 1.3 mu m emission and the lifetime was 25 mu s, resulting in a quantum efficiency of 7%. This value is higher than that of the Pr3+:(1)G(4) level in ZBLAN glass with beta = 60%.