Highly confined waveguides and waveguide bends in three-dimensional photonic crystal

We demonstrate a method to create a highly confined waveguide with sharp bend in three-dimensional photonic crystal. By theoretical calculation, we show that a single-mode waveguide can be created in the stacked-bar structure by removing one stripe. Crossing waveguides of the adjacent layers can create the waveguide bend and by this way, the guided modes after and before the bend remain the same so that the transmission through the bend is optimized. These results provide very important guidelines for designing a three-dimensional photonic crystal waveguide. (C) 1999 American Institute of Physics. [S0003-6951(99)00550-1].