Off-plane directional coupler in woodpile structure

Directional couplers are essential building blocks for large scale optical integration equipments. Using finite difference time domain method, off-plane directional coupler formed by two straight waveguides in woodpile structure are designed, analyzed, and simulated. First, the coupler length for different frequency is given through analyzing transmission spectrum and field distribution. The results show that the light wave can be coupled from input waveguide to output waveguide. At the same time, off-plane power splitters and wavelength division multiplexers based on directional coupler are designed, simulated and analyzed. They also show good energy transfer property.