Spectroscopy and quantum efficiency of halide-modified gallium-lanthanum sulfide glasses doped with praseodymium

Abstract

Gallium-lanthanum sulfide (GLS) glasses are one of the most promising candidates for use in efficient 1.3 μm optical fiber amplifiers. In this paper we present a study of the optical properties of Pr3+-doped GLS, modified using alkali halides. It has previously been shown that the addition of halide modifiers to GLS has a beneficial effect on the glass- forming and bulk optical properties. In this paper we show that the optical emission properties of the Pr3+ dopants are altered by the addition of halide modifiers, but are still considerably better than either ZBLAN or oxide-modified GLS. The quantum efficiency of the 1G4-3H5 1.3 μm transition, which is the most important parameter for efficient amplification, has been measured at 55% for these glasses, compared to 65% in pure GLS. We will present studies of the effect of compositional changes on the Raman spectrum of the glass, and on the radiative and non- radiative decay of the Pr3+ ion, and show how these are related to changes in the structure of the glass.