Photorefractive effects in ±-phase proton exchanged LiNbO<sub>3</sub> waveguides have been studied at temperatures between 50°C and 150°C, a range of major interest in connection with the fixing process. Experiments of recording, light and dark decays, fixing and optical developing, have been carried out. On increasing the temperature, the recording kinetics exhibits a transient peak in the diffraction efficiency η<sub> <i>max</i> </sub>, the rise and decay times being progressively shorter at higher temperatures. After fixing at 90°C (where η<sub> <i>max</i> </sub> ≈ 6%) and subsequent optical developing at room temperature, the η<sub> <i>dev</i> </sub> value rises up to 2.5η<sub> <i>max</i> </sub> ≈ 15%. This value decays in a few hours in the dark, but can be fully recovered by further developing. As in bulk crystals, the results can be qualitative understood in terms of the standard proton-fixing model.

© 2003 Optical Society of America

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