Spectroscopic and pump power dependent upconversion studies of Er3+-doped lead phosphate glasses for photonic applications

Abstract

Er3+-doped lead phosphate glasses (PKAPbNEr) were prepared by a melt quenching technique and their spectroscopic properties were investigated for 1.54 μm fiber amplifier applications. Judd-Ofelt (JO) analysis was carried out from the absorption spectra of 1.0 mol% Er2O3-doped glass and the derived JO parameters were found to be Ω2 = 4.7, Ω4 = 0.7 and Ω6 = 1.2 (×10−20 cm2). The transition probabilities, branching ratios and radiative lifetimes for several excited states of Er3+ were predicted using JO parameters and refractive index. The stimulated emission-cross section of the green emission (4S3/2 → 4I15/2) has been determined to be 3.31 × 10−21 cm2. Absorption cross-section (σabs(λ)), emission cross-section (σemi(λ)) and gain bandwidth (FWHM × σemi(λ)) of 4I13/2 → 4I15/2 transition at 1.54 μm were deduced from the McCumber theory and found to be 4.97 × 10−21, 6.63 × 10−21 and 267 × 10−28 (cm2), respectively. The decay curves exhibit single exponential nature and the lifetimes were determined to be 4.50, 4.57, 2.61, 2.06, 1.48 and 1.04 ms for 0.05, 0.1, 0.5, 1.0, 2.0 and 4.0 mol %, respectively, for Er2O3-doped lead phosphate glasses. The results confirm that the present Er3+-doped lead phosphate glasses could be considered as promising candidates as gain media for photonic applications.