Strongly nonlinear effects in non-uniform waveguide arrays

We observed a bound state in a waveguide array localized on a guide with reduced effective index. We designed the array in such a way that the optical nonlinearity may compete with the linear guiding mechanism, allowing for strongly nonlinear effects. We demonstrate that considerable portions of the guided power escape from the defect state due to the action of the nonlinearity. We found a power dependent high contrast up switching in one of the waveguides. This is a remarkable achievement in a real device, which presents both dispersion as well as linear and nonlinear losses