[Studies on characteristics of proton-exchanged LiNbO3 optical waveguides by X-ray diffraction and infrared absorption spectroscopy].

The characteristics of proton-exchanged and annealed proton-exchanged LiNbO3 optical waveguides were studied by X-ray diffraction and infrared absorption spectroscopy. The X-ray diffraction experiments show that there are diffraction peaks of Lil-x, HxNbO3 on the left of the main peak of the LiNbO3 crystal substrate. This result means that the crystal lattice constant of the layer Li1-x, Hx NbO3 is little larger than that of the LiNbO3 crystal substrate, resulting in a stress.

[Infrared absorption spectroscopy of optical waveguide in proton-exchanged LiNbO3].

Z-cut proton-exchanged LiNbO3 optical waveguides exchanged with different proton sources mixed with adipic acid and benzoic acid in different mol ratios were analyzed by infrared absorption spectroscopy. The result shows that there is an absorption peak of OH- free group at 3500 cm(-1) with the characteristic of substitute protons, and the absorption peak of H-bond is nearby 700 cm(-1) with the characteristic of packing protons. The different mixing ratios and different concentrations of H+ in the proton source, result in different proton-exchanged velocities and bring on the change in these absorption peaks.