Sensitizing effect of Yb3+ ions on photoluminescence properties of Er3+ ions in lead phosphate glasses: Optical fiber amplifiers

Abstract

The Er3+/Yb3+-codoped lead phosphate (PPbKANErYb) glasses have been prepared by using melt quenching technique and characterized through spectroscopic studies such as absorption, emission, decay and upconversion measurements. An intense near-infrared (NIR) emission at 1.53 μm was observed which has been explained based on the effective energy transfer from Yb3+ to Er3+ ions. The absorption (4I15/2 → 4I13/2) and emission cross-section (4I13/2 → 4I15/2) of 1.53 μm emission band was calculated and found to be of the order of 6.76 × 10−21 and 7.9 × 10−21cm2, respectively, by using the McCumber theory. The PPbKANErYb glasses exhibit higher luminescence intensity (more than 3 times) and full width at half maxima (55 nm) compared to 1.0 mol % Er3+ singly doped glass (50 nm). All the decay curves of the 4I13/2 level exhibited single exponential nature and the lifetimes increased (1760, 1776, 1942 and 2830 μs) with the increase of Yb2O3 (0.5, 1.0, 2.0 and 3.0 mol %) concentration. Intense red band at 670 nm corresponding to 4F9/2 → 4I15/2 transition and green emission bands at around 530 and 555 nm corresponding to 2H11/2 → 4I15/2 and 4S3/2 → 4I15/2, transitions, respectively, have been observed under the excitation of 980 nm. The intensity of the upconversion emissions is found to be increased with the increase of Yb3+ ion concentration and its mechanism have been explained. The luminescence decay curves of the 4S3/2 → 4I15/2 upconversion luminescence of Er3+/Yb3+ codoped PPbKAN glasses under the infrared excitation of 980 nm have been evaluated. The results reveal that the investigated glasses might be potential candidates for optical fiber amplifiers/laser sources at 1.55 μm band.