Competence Center for Micro- and Nanotechnologies

An innovative approach using the vapor axial deposition (VAD), for the preparation of silica‐based high‐power fiber laser preforms, is described in this study. The VAD uses a plasma deposition system operating at atmospheric pressure, fed by a single, chemically adapted solution containing precursors of laser‐active dopants (e.g., Yb2O3), glass‐modifier species (e.g., Al2O3), and the silica matrix. The approach enables simultaneous doping with multiple optically active species and overcomes some of the current technological limitations encountered with wellestablished fiber preform technologies in terms of dopant distribution, doping levels, and achievable active core diameter. The deposition of co‐doped silica with outstanding homogeneity is proven by Raman spectroscopy and electron probe microanalysis. Yb2O3 concentrations are realized up to 0.3 mol% in SiO2, with simultaneous doping of 3 mol% of Al2O3.