Coupled Mode Equations for Nonlinear Directional Couplers

F. J. Fraile-Pelaez and G. Assanto

Appl. Opt. 29, 2216-2217 (1990)


We point out some inconsistencies in the usual coupled-mode formulation employed to model the nonlinear behavior of symmetric directional couplers. In particular, we show that special care is required when neglecting some of the nonlinear terms in the equations.