Analyzing Bent Waveguide Using Variational Effective Index Method and Cylindrical Perfectly Matched Layers

An efficient mode solver for the cross-section mode of three-dimensional bent waveguide is proposed and validated. The technique is based on vectorial slab mode expansion and perfectly matched layer in cylindrical coordinate system. Numerical simulations of rib and ridge waveguides are performed in order to demonstrate the accuracy of the method. The correlation coefficient between simulation results and literature results is 0.9995. Due to the variable separation of slab mode expansion and the absorption of perfectly matched layer boundary, the mode solver provides an efficient and reliable estimation of the modal field profile and curvature loss of bent waveguide.