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Abstract: A silicon-based horizontal multiple-slotted waveguide with slanted sidewalls is analyzed by using a full-vectorial mode solver based on the finite element method. The results show that the mode classification of the present waveguide structures is different from that of the conventional ones (e.g., typical rib waveguides, optical fibers), both symmetric and anti-symmetric fundamental (and higher-order) quasi-TE and quasi-TM modes exist due to the strong coupling of high-index silicon layers. The field distributions, effective indexes, and optical field confinement factors, both in quasi-TE and quasi-TM modes, as functions of the top width and sidewalls angle of the waveguides, and the refractive index and thickness of the slots are investigated in detail, where the single-mode regime, non-birefringence condition, and maximum optical confinement factor are obtained. From the numerical results, a single-mode waveguide structure for fundamental symmetric quasi-TM modes with the power confinement factor of 80% and the normalized power density of 120μm−2 is achieved. [Copyright &y& Elsevier]

Abstract: A full-vectorial mode solver in terms of the transverse magnetic field components for optical waveguides with transverse anisotropy is described by using the multidomain spectral collocation method based on Chebyshev polynomials. The waveguide cross section surrounded by the perfectly matched layers is divided into suitable number of homogeneous rectangles, and then connected with by imposing the continuities of the longitudinal field components at the dielectric interfaces shared by the adjacent rectangles, resulting in a generalized matrix eigenvalue problem. To validate the established method, results of an anisotropic square waveguide and a magnetooptic rib waveguide are presented and compared with those from the full-vectorial finite difference method, full-vectorial beam propagation method, and the experimental data. [Copyright &y& Elsevier]

Abstract: A full-vectorial (FV) analysis of optical dielectric waveguide bends by using finite difference (FD) method in terms of magnetic field components is developed in a local cylindrical coordinate system. The perfectly matched layer absorbing boundary conditions via the complex coordinate stretching technique are incorporated into the FV wave equations for effectively demonstrating the leaky nature of waveguide bends, and a six-point FD scheme is constructed to approximate the cross-coupling terms for improving the convergent behavior. The leaky modes of a typical rib waveguide bend are calculated and the complex propagation constants and the field patterns for TE- and TM-like modes are obtained. Solutions are good agreement with those from the film mode matching method, which shows the validity and utility of the established method. [Copyright &y& Elsevier]

Abstract: The mapped Galerkin method in solving the full-vector and quasi-vector wave equations in terms of transverse magnetic fields (H-formulation) for optical waveguides with step-index profiles is described. By transforming the whole x–y space onto a unit square and using two-dimensional Fourier series expansion, the modal distributions and propagation constants for optical waveguides are obtained in the absence of boundary truncation. Results for step-index circular fiber, buried rectangular waveguide, and optical rib waveguide are presented. Solutions are good agreed with exact solutions and numerical results by using vector nonlinear iterative method, Fourier operator transform method, and vector beam propagation method. [Copyright &y& Elsevier]