Modeling of Single-and Multimode Photonic-Crystal Planar Waveguides with Plane-wave Admittance Method: Losses and Modes Coupling

This work presents the application of the plane-wave admittance method (PWAM) to modeling the propagation of light and optical losses in photonic crystal waveguides. Both single- and multimode waveguides are analyzed and in the latter case the increase of losses due to the mode coupling is determined. As such mode coupling introduces a photonic mini stop band, its formation is analyzed. It is found that such a mini stop band can disappear when the complex propagation constant is allowed, which stays in agreement with the coupled-mode theory