We report laser action in a Ti-diffused LiNbO(3) waveguide doped with trivalent Yb ions by thermal indiffusion. Lasing was observed at 1008, 1030, and 1060 nm with thresholds as low as 15-mW launched pump power. We reduced photorefractivity, which initially permitted only intermittent lasing, by annealing the sample in wet O(2). The annealed sample lased continuously in a cavity formed by high-ref lectivity mirrors; however, with a 7% output coupler the output power exhibited instabilities. The greatest value of the output power observed under these conditions was consistent with a slope efficiency of ~16% with respect to absorbed power.

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We have made chromium-doped, silica-based preforms and optical fibres by Modified Chemical Vapour Deposition and have studied the influence of the chemical composition of the doped region on the Cr-oxidation states and the spectroscopic properties of the samples.