Beam dynamics in nonlinear coupled slab waveguides: three-dimensional variational analysis

The behavior of a three-dimensional optical beam propagating in a nonlinear coupler is investigated with a variational approach. Through this approach it is possible to go beyond the limits of the coupled-mode formalism and retain, at the same time, a simple description of the physical problem. As a result of our analysis, we determine the self-trapped modes of the device.