Spectral characterization of Yb–doped silica layers for high power laser applications

• Published in: Optical materials 2011-01, Vol.33 (3), p.438-443
• Main Authors: Eger, David, Atar, Gil, Bruner, Ariel, Sfez, Bruno, Juwiler, Irit, Kokki, Temmu, Kykkänen, Pekka
• Format: Article
• Language: English
• Subjects: Aluminum; Amplifiers; Fluorescence; Laser beam annealing; Laser heat-treatment; Noise levels; Optical slab waveguides; Photoluminescence; Rare earth metals; Rare-earth doped silica; Silicon dioxide; Sintering; Spectroscopy; Ytterbium
• ISSN: 0925-3467; 1873-1252
• DOI: 10.1016/j.optmat.2010.10.012

Thick silica layers, doped with rare-earth elements are required as active media for high power waveguide lasers and amplifiers. In this work, Yb/Al-codoped silica particles were deposited on pure silica wafers, followed by high temperature sintering and post-sinter laser annealing treatment. The optical properties of the layers were monitored at different stages of the process using transmission spectrometry in the near IR to UV range, micro-Raman spectroscopy, fluorescence spectrum, and decay measurements. Evolution of the Yb3+ ion fluorescence and stabilization of the Si:O bonds as a result of the sintering process were observed. Measurements of 30μm thick layers showed high Yb absorption of 500dB/m at 980nm. The fluorescence lifetime was close to 1ms and the propagation loss was less than 20dB/m at 633nm, currently limited by the measurement system. The results show that a potential material for high power applications has been achieved.