Thermally induced dephasing of high power second harmonic generation in MgO:LiNbO3 waveguides

High power second harmonic generation(SHG) in MgO-doped LiNbO3 waveguides is investigated using a three-dimensional(3D) coupled thermo-optical model.Simulations performed for a 1111.6-nm fundamental laser show the in?uence of the absorptions and the thermally induced dephasing on the conversion efficiencies of the different waveguides.The onset of the thermally induced dephasing effect for each waveguide is also indicated.As a result of high light intensity in the waveguide,nonlinear absorptions are identified as the possible main factors in efficiency losses in specific cases.