Energy flow in photonic crystal waveguides

Theoretical and numerical investigations of energy flow in photonic crystal waveguides made of line defects and branching points are presented. It is shown that vortices of energy flow may occur, and the net energy flow along the line defect is described via the effective propagation velocity. Single-mode and multimode operations are studied, and dispersion relations are computed for different waveguide widths. Both strong positive, strong negative, and zero dispersion are possible. It is shown that geometric parameters such as the nature of the lattice, the line defect orientation, the defect width, and the branching-point geometry have a significant influence on the electrodynamics. These are important issues for the fabrication of photonic crystal structures.