Design of compound-defect waveguides in threedimensional photonic crystals

We designed three-dimensional (3D) photonic crystal (PC) waveguides by simultaneously introducing one acceptor-type and two donor-type line defects. The waveguides have an extremely large singlemode bandwidth, which covers more than 90% of the complete photonic band gap. The relatively large group velocity and the mode-field localization in the air core should prevent unintended nonlinear phenomena for ultra-short pulse propagation. These promising characteristics could only be achieved by using 3D PCs, which have the advantages of complete light confinement and no restrictions of the light cone.