We report a theoretical analysis of third-harmonic generation (THG) in a LiNbO<sub>3</sub> channel waveguide with a quasi-periodic grating. For efficient third-harmonic conversion, apart from a large nonlinear coefficient and quasi-phase-matching conditions, a large overlap integral between the interacting waves is needed, which can be achieved in a microstructured waveguide. The dependence of the optimum interaction length on the fundamental power is described. The effects of the width of the mask opening and of the annealing depth on the THG are determined. The relationship among the bandwidths and the fundamental wavelength and the operating temperature as well as the width of the mask opening are also given. The results might be useful for the fabrication of a practical device.
© 2004 Optical Society of America
(190.0190) Nonlinear optics : Nonlinear optics
(190.2620) Nonlinear optics : Harmonic generation and mixing
(190.4360) Nonlinear optics : Nonlinear optics, devices
(190.4400) Nonlinear optics : Nonlinear optics, materials
Guo-Ding Xu, Yue-Hua Wang, Yong-Yuan Zhu, Shi-Ning Zhu, and Nai-Ben Ming, "Third-harmonic generation in a LiNbO3 channel waveguide with a quasi-periodic grating," J. Opt. Soc. Am. B 21, 568-573 (2004)