Wavefront Matching Method Based on Full-Vector Finite-Element Beam Propagation Method for Polarization Control Devices

We developed a wavefront matching (WFM) method based on the full-vector finite-element beam propagation method (BPM). The WFM method is one of the optimization algorithms based on BPM, and it can deterministically design optimum waveguide structures from desired characteristics. The developed WFM method can be applied to optical waveguides with high refractive-index contrast and polarization control devices, which require full-vector analysis. In this paper, the principle and design procedure of the full-vector WFM method are described. Its validity and effectiveness are demonstrated by designing polarization control devices, such as a polarization converter based on a vertical asymmetric taper waveguide and a polarization splitter-rotator based on taper and Y-branch waveguides.