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With a view to make the finite-clement analysis of anisotropic graded-index channel waveguides efficient, quadratic triangular elements are used. In addition, an application of the numerical integration formula by Hammer et al. is attempted for the integration calculation necessary for formation of the element matrix. Numerical investigation has been carried out for a Ti-diffused LiNbO3 waveguide. It is confirmed that highly accurate solutions can be obtained with small-scale computation in the presented method. Also, it is found that, lithe isotropic approximation frequently employed in the past is still used, significant differences appears in not only the phase constant of the guided mode but also in the coupling length of the optical directional coupler indispensable for configuration of the optical integrated circuit, compared with the results considering the anisotropy. Further, the validity of the results by the scalar finite element method is confirmed by comparison with the results by the vector finite difference method. [ABSTRACT FROM AUTHOR]

To evaluate nonreciprocal phase characteristics of a magneto-optic channel waveguide, the formulation of a finite-element method based on a scalar wave approximation is discussed here for the first time. This problem is ascribed to the problem of solving a nonlinear eigenvalue equation. However, a simple iterative method is proposed here for solving the nonlinear eigenvalue equation. The validity and usefulness of the present method are demonstrated in analyzing magneto-optic rib wave- guides and magneto-optic ridge waveguides. A discussion to increase a nonreciprocal phase shift in those wave- guides also is given. [ABSTRACT FROM AUTHOR]