Time Resolved Switching Characteristic Of The Nonlinear Directional Coupler Under Consideration Of Susceptibility Dispersion

The nonlinear directional coupler in either of its two forms, as fiber coupler [3] or in­ tegrated optic coupler (4], has assumed increased importance as an ultrafast optical switch in recent years. Most of the theoretical investigations are based on the stationary usual nonlinear coupled-mode theory introduced by Jensen [l]. But the temporal switching characteristics of the nonlinear coupler are determined by self-phase modulation, and waveguide and susceptibility dispersion. That is why we introduce for the computation of the temporal behaviour of the switching process from the limits of stationary through quasistationary [3] up to ultrafast excitations [2] a system of nonlinear coupled equations for the basis mode amplitudes in the frequency domain.