Three-dimensional beam propagation analysis of quasi-phase matched second harmonic generation devices with triangular and semi-circular domain inversion profiles

A three-dimensional beam propagation method based on a finite element schem e is described for the analysis of second harmonic generation devices. For the wide-angle beam propagation analysis, the Pade approximation is applied to the differential operator along the propagation direction. In order to avoid spurious reflection from the computational windows edges, the transpa rent boundary condition is introduced. Numerical results are shown for quas i-phase matched second harmonic generation devices using periodically domai n-inverted LiNbO3 and LiTaO3 waveguides. The influences of the shape of dom ain-inverted regions and the inversion width on the conversion efficiencies are investigated in detail.