Coupled-mode analysis of two-parallel post-wall waveguides

The guided modes supported in a coupled two-parallel post-wall waveguides are analyzed by using a coupled-mode theory for coupled two-dimensional photonic crystal wave guides. The coupled-mode equations, which govern the evolution of the modal amplitude of individual post-wall waveguides, are derived in self-contained way on the basis of eigenmode fields of each single waveguide in isolation. Numerical examples show that for various configurations of post-walls, the solutions of the coupled-mode equations are in very close agreement with those obtained by the rigorous numerical analysis.