Energy transfer and 1.48 mu m emission properties in chalcohalide glasses doped with Tm3+ and Tb3+

Abstract

Emission characteristics and energy transfer in chalcohalide glasses doped with Tm3+ and Tb3+ were investigated and their potential as S-band fiber-optic amplifiers was evaluated. Upon the addition of CsBr into sulfide glass, intensity of the 1.48 mum emission (H-3(4) --> F-3(4) transition) from Tm3+ increased. At the same time, the lifetime of the H-3(4) level increased to 1.2 ms, approximately eight times longer than the value obtained from sulfide glass. Quantum efficiency of the transition also increased to approximately 90%. Cross relaxation between the H-3(4) and F-3(4) levels was significant when Tm3+ ion concentration exceeded 0.2 mol%. Population density of the F-3(4) level in Tm3+ decreased upon the addition of Tb3+ due to the TM3+:F-3(4) --> Tb3+:F-7(0.1.2) energy transfer. Population inversion became possible when Tb3+ concentration reached 0.11 mol%. (C) 2003 Elsevier B.V. All rights reserved.