Analysis of optical waveguide discontinuities using Denman-Beavers iterative scheme

A new approach for solving the optical waveguide discontinuity problems is proposed, where the field-based operator techniques are employed. Instead of using Padé approximation, the square roots of the characteristic matrices are approximated by the Denman-Beavers iterative scheme with a branch-cut rotation in the complex plane. Numerical results show that the present scheme is more accurate and stable than the widely used Padé approximation.