For applications in fiber lasers and amplifiers, silica glass remains a perspective host for rare-earth ions thanks to favorable material properties. However, the luminescence of RE ions is hindered by the high phonon energy of silica lattice and low solubility of RE ions, which cause luminescence quenching. Pure silica thus needs to be co-doped with suitable additives such as Al₂O₃, which form a beneficial low-phonon environment and increase the solubility of RE ions. Luminescence lifetime is one of the most important parameters to determine the suitability of RE-doped silica fibers for laser operation. Optical fibers with higher luminescence lifetime typically exhibit higher values of slope efficiency and lower laser threshold. It was previously shown that the environment of Tm³⁺, Ho³⁺ or Yb³⁺ ions and luminescence lifetime may be significantly affected by fabrication processing at high temperatures, probably due to the chemical changes occurring in the matrix. However, the effect of fabrication processing on the spectroscopic properties of another important RE ion, Er³⁺, is different to the other ions and remains unclear. In this contribution, we present a study on the fluorescence lifetime of a highly-doped optical fiber prepared by the MCVD method combined with nanoparticle-doping. The fluorescence lifetime of Er³⁺ was studied in several stages of fabrication processing. The influence of fabrication processing on the fluorescence lifetime of Er³⁺ ions was analyzed and discussed.