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We propose a novel numerically efficient model for accurate characterization of leaky modes in optical waveguides. Within the context of finite elements, the mesh boundaries are truncated using complex infinite elements (CIEs). The CIE is based on adopting the homogeneous solution of the wave equation with the shape function of infinite elements to accurately and physically model semi-infinite subdomains instead of placing an artificial layer such as PML. The proposed treatment can be easily implemented and requires less computational resources compared to other conventional mesh truncation methods. The accuracy and rigor of our approach are demonstrated through studying different leaky waveguides' configurations. [ABSTRACT FROM AUTHOR]

A novel approach is presented to solve an algebraic problem related to complex finite element analysis of periodic structures. This approach turns the quadratic eigen problem into a linear eigen problem of the same dimension and also exploits the sparsity of matrices which reduces the computation time enormously. An algorithm is also proposed that generates the dispersion diagram automatically. The method is applied to fairly simple singly, doubly, and triply periodic structures and the results agree well with those obtained by the dense-matrix approach. A more complicated device, a mushroom structure for use in the power distribution networks of electronic circuits, is also analyzed. The computational complexity of the new method is estimated to be n^1.6, where n is the dimension of the matrix problem. [ABSTRACT FROM PUBLISHER]