T.R. Volk - Dr.Sc. (Phys.-Math.), Professor, Head of the laboratory, Shubnikov Institute of Crystallography of the RASciences. E-mail: volk@crys.ras.ru R.V. Gainutdinov - Ph.D. (Phys.-Math.), Senior Researcher, Shubnikov Institute of Crystallography of the RAS. E-mail: radmir@crys.ras.ru L.S. Kokhanchik - Ph.D. (Phys.-Math.), Senior Researcher, Institute of Microelectronics Technology and High Purity Materials of the RAS. E-mail: mlk@iptm.ru Ya.V. Bodnarchuk - Post-graduate Student, Shubnikov Institute of Crystallography of the RAS. E-mail: deuten@mail.ru E.D. Mishina - Dr. Sc. (Phys.-Math.), Professor, Moscow State Technical University of Radio Engineering, Electronics and Automation. E-mail: mishina_elena57@mail.ru S.D. Lavrov - Post-graduate Student, Moscow State Technical University of Radio Engineering, Electronics and Automation. E-mail: sdlavrov@mail.ru F. Chen  Professor, Shandong University, Jinan, China. E-mail drfchen@sdu.edu.cn

We present the results of studies in planar optical waveguides fabricated by He-ion implantation in X-cut LiNbO3 crystals and Z-cut SBN crystals. The thickness of the waveguide is confined by the depth D of He-implanted damaged layer which for the used ion-beam energy 450 keV was of 1,4 and 1 μm in LiNbO3 and SBN, respectively. Domain gratings with the period Λ = 4 µm were recorded in He-implanted samples by electron-beam (EB) irradiation in SEM with acceleration voltages U in the range from 5 to 25 kV. The domain thickness Td is determined by U and in the given U range was varied from 0,2 to 4-5 μm. Gratings characteristics were measured by PFM and confocal SHG microscopy on reflection. It was shown that the highest grating regularity is achieved in the case that the domain growth occurs beyond the He-implanted damaged barrier, i. e. at Td ≤ D, which in the given case corresponds to U = 10 and 15 kV. Otherwise (Td > D), the domain frontal and sideways motion occurs over the damaged layer which affects the growth kinetics. As a result, the gratings become irregular. This conclusion permits us to match the EB irradiation conditions to the waveguide thickness to provide the optimum grating characteristics.

 

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