Recently, nanocomposite glass materials embedded with silver particles and lanthanide ions have been widely investigated. The main interest is a surface plasmon resonance (SPR) phenomenon, which, as a result of nanometric particles’ interaction with external electromagnetic waves, has led to the enhancement of rare-earth luminescence. In most works, nanoparticles are created in photonic glass by annealing for various times; however, the most discussion of this field in the literature is dedicated to the practical use of plasmonic effect in optical fibers. In this paper, the effect of silver ions on the luminescent properties of europium ions in antimony-germanate-borate (SGB) glass fibers is presented. The glass was synthesized by a standard melt-quenching technique, and glass fiber was drowned at 580 °C. The analysis of Ag+ ions content, as well as heat-treatment (hT) time, show an increase of almost 36% in emissions at 616 nm for glass fiber co-doped with 0.1Ag+/0.2Eu3+ ions after a 2 h annealing process. In the experiment, the interaction mechanism was investigated in terms of localized SPR, in each step of the glass fiber fabrication process. Moreover, we demonstrate that the self-assembling of silver nanoparticles onto a glass fiber surface is possible only for fiber co-doped with 0.6Ag/0.2Eu ions. This non-conventional, bottom-up technique of thin film was analyzed by Scanning Electron Microscopy (SEM) measurements.