Numerical Simulations of Resonant Electromagnetic Fields in the Waveguide With Random Shape Boundary

The reflection and transmission of guided mode in the 2-D single-mode waveguide whose boundary is random shape is numerically simulated. Since the boundary element method based on the guided-mode extracted integral equation (GMEIE) is employed, the boundary condition on the random boundary is rigorously satisfied. The dependence of the transmission coefficient on the amplitude of the random boundary is investigated. It is found that strong resonances with high Q-factor occur even for slightly corrugated boundaries and cause the extremely small transmission (high reflection). These resonances are created by the existence of the region where the second mode can propagate in the random waveguide. The frequency characteristics of these resonances are examined in detail.