Three-dimensional analysis of all-optical switching device in directional coupler with localized optical nonlinearity

All-optical switching devices using waveguide directional coupler with localized optical nonlinearity are analyzed by using three-dimensional modified explicit finite difference beam propagation method (MEFD-BPM) and new transparent boundary condition (TBC) method. The MEFD and new TBC are explicit, stable, and very efficient. Particularly, the new TBC can easily be implemented and greatly reduces the computation time without any additional error. The new TBC has been found, after several other trials, to yield numerical stability.