Erbium‐Doped Fluoroborate Glasses for Near Infrared Broadband Amplifiers

Abstract

Erbium (Er3+)‐doped alkali lead tellurofluoroborate (RLTB) glasses were prepared and characterized systematically through optical absorption and emission measurements. The emission spectra in the range 450–900 and 1400–1800 nm were recorded by exciting the samples with 532 nm (Nd : YVO4 crystal) and 514.5 nm (Ar+ laser), respectively. Applying Judd–Ofelt analysis, the intensity parameters have been determined using experimental oscillator strengths of absorption bands. From the Judd–Ofelt intensity parameters, some important fluorescence properties such as spontaneous transition probabilities, radiative lifetimes and luminescence branching ratios for the 4S3/2→4I15/2 (0.55 μm), 4S3/2→4I13/2 (0.85 μm), and 4I13/2→4I15/2 (1.54 μm) emission transitions of Er3+ ion in RLTB glasses have been calculated. The continuous pumping of the samples results in fast nonradiative decay through 2H11/2→4F9/2 (~3500 cm−1) transition, which in turn causes the population of Er3+ ions from 2H11/2 state to the higher 4F3/2 state. The emission cross sections determined for the 4I13/2→4I15/2 (1.54 μm) transition using the McCumber theory are in good agreement with the values obtained from the Judd–Ofelt analysis. From evaluated radiative parameters, it is suggested that these RLTB glasses are more suitable candidates for 0.85 and 1.54 μm broadband optical amplifiers.