Efficient Simulation of 3D Electro-optical Waveguides Using the Effective Refractive Index Method

3D FEM simulation of millimeterscale, complex electro-optically induced waveguide based devices demands the use of grids with more than several million nodes. Hence, the simulation could take substantial time and require large amounts of available memory. This paper presents a computation algorithm based on the conversion of an initial 3D waveguide structure into an analogous 2D structure, where the wave propagation on the ‘reduced’ dimension is described by an effective refractive index. It is shown that with the proposed algorithm the computing efficiency could be improved. Moreover the algorithm could be successfully used to simulate large-size passive or electro-optically active waveguide structures. For an electro-optical waveguide coupler, we could demonstrate a good agreement between simulated and calculated coupling length.