Simulation of Waveguide Crossings and Corners With Complex Mode-Matching Method

The complex mode-matching method is applied to simulation of optical waveguide structures with intersecting structures such as crossings and corners. It is demonstrated that field propagating along the direction perpendicular to the incident waveguide can be represented adequately by the complex modes defined in the incident waveguide and, therefore, can be simulated accurately by the complex mode-matching method. Power conservation is illustrated by way of examples to prove the self-consistency of the complex mode-matching method. Radiation field perpendicular to the incident waveguide axis in waveguide crossings and corners is simulated by this method and validated by the finite-difference time-domain method.