Electric field periodical poling of lithium niobate crystals after soft-proton-exchanged waveguide fabrication
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- Caballero-Calero, O., Kösters, M., Woike, T. et al. Appl. Phys. B (2007) 88: 75. doi:10.1007/s00340-007-2658-y
We report on the periodic polarization of α-phase proton- exchanged LiNbO3 planar waveguides down to 5 μm period lengths using structured electrodes and electrical fields. Unlike a majority of previous work, room-temperature electric field poling has been carried out after waveguide fabrication. Chemical etching of the large guiding surface has revealed homogeneous and high-quality domains with duty cycles close to 0.5. Moreover, it was verified by diffraction techniques and etching that the domain structure is preserved more than 2 μm along the thickness of the waveguide. The excellent optical performances of single-domain α-phase waveguides were not affected by the periodic poling.