Power‐dependent switching in a coherent nonlinear directional coupler in the presence of saturation

The fundamental limitations for all‐optical switching in a nonlinear directional coupler due to the saturation of the nonlinearity have been obtained by solving analytically the nonlinear coupled‐mode equations. We found that there is a minimum value required for the saturation index change to obtain efficient switching, and that the number of powers at which switching occurs at one beat length can double.