All-optical devices using nonlinear fiber couplers

The coupler parameters for various all-optical devices using weakly-coupled nonlinear fibers are anticipated from a graphical method of representing extrema of core power called the power flow portrait. These devices are then analyzed in detail both analytically and numerically. Devices considered include a bandpass power filter, various schemes for logic gates, and a novel power-dependent switch utilizing saturation. By anticipating the mode portrait required to obtain the desired output characteristics, the required device and material parameters needed to achieve these portraits are determined, in the case of the bandpass power filter, from a catalog of nonlinear directional coupler mode portrait types, and by extrapolation in the case of the power-dependent switch