Er 3 + -doped boro-tellurite glass for optical amplification in the 1530–1580nm

Abstract

The paper investigates the influence of boric oxide (B2O3), which has a phonon energy of 1500cm−1, on enhancement in the population of the I13∕24 level via the increased multiphonon relaxation in the Er-ion doped tellurite fibers. The paper discusses the structural compatibility of TeO4 structures with BO4 structural units and, therefore, the limitation on the solubility limits of boric oxide in the glass. In the present investigation the optimal composition demonstrates the minimum devitrification tendency in the glassy state that has one of the largest multiphonon relaxation rates. A comparison of lifetimes of I11∕24 level is also made for other tellurite and boro-tellurite compositions. The experimental data show that the transition rate at I11∕24→I13∕24 dramatically increased by incorporating 15mol% B2O3 without sacrificing the spectroscopic properties of glass. The lifetime at I11∕24 transition level decreased from 213to54μs when B2O3 is introduced into tellurite glass. We also report the calculated Judd–Ofelt parameters and the radiative transition rates, which increased by incorporating B2O3 in the tellurite glass. Gain measurements in single-mode boro-tellurite fibers show an increase in peak internal gain from 10to13dB and also, the overall gain spectrum broaden across the L band (1565–1605nm).