Structural and spectroscopic studies on the concentration dependent erbium doped lithium bismuth boro tellurite glasses for optical fiber applications

Abstract

High gain and better optical properties are the key requirement for the optical fibers and amplifiers to meet the current technological demand. In this regard, in the present investigation, erbium doped lithium bismuth boro tellurite glasses are prepared using melt-quenching technique. The prepared glasses were extensively characterized through, XRD, DSC, UV–Vis-NIR and also Luminescence and Decay techniques to study the concentration dependent structural, optical and luminescence properties. Prepared glasses are amorphous in nature and the corresponding band gap energy decreases with erbium concentration indicates increase of metallicity of the glasses. FTIR studies show different vibration modes majorly borate groups. In addition, Judd-Oflet theory is employed to derive different optical parameters such as intensity parameters, oscillatory strength, branching ratio, stimulated emission cross section and time decay to validate the experimental results of prepared glasses towards optical fiber applications. Estimated values of Stimulated emission, effective band width and gain band width values found higher when compared with other host glasses. Results also show that, 100% branching ratio is obtained for the highest intense peaks corresponds to the transition 4I13/2 → 4I15/2 in NIR luminescence spectra for 1.53 μm broad band. For power dependent 980 nm excitation, up-conversion spectra shows two transitions, namely 4S3/2 → 4I15/2 and 4F9/2 → 4I15/2 at 541 and 655 nm corresponds to green and red emission respectively. From the McCumber’s theory, the absorption and emission cross section more comaprable values are obtained for 1 mol% erbium doped glass. About 40% population inversion is obtained with C band from 1500 to 1550 nm. The results suggests that, the prepated glasses are the potential candidates for optical fiber applications.