Photorefractive recording and light and dark erasures have been measured in unannealed α-phase proton-exchanged LiNbO3 waveguides. The saturation index change, Δns≅9×10−6, is independent of the light intensity within the studied range, 0.3–50 W/cm2. The time dependencies are well represented by the sum of two exponential components. After complete optical erasure, diffraction efficiency η increases in the dark (i.e., dark developing) up to ∼17% of the saturation value ηs≅0.12 and then decays to zero in ∼4 h. All experimental results are reasonably well simulated by a model in which the Fe2+/Fe3+ light-induced charge distribution is compensated for by a light-insensitive species (ionic charges or holes) that is mobile at room temperature.
© 2000 Optical Society of America
(130.3130) Integrated optics : Integrated optics materials
(130.3730) Integrated optics : Lithium niobate
(190.4400) Nonlinear optics : Nonlinear optics, materials
(190.5330) Nonlinear optics : Photorefractive optics
A. Méndez, A. García-Cabañes, M. Carrascosa, and J. M. Cabrera, "Photorefractive charge compensation in α-phase proton-exchanged LiNbO3 waveguides," J. Opt. Soc. Am. B 17, 1412-1419 (2000)