Observation of nonlinear localized modes in an electrical lattice

We study a discrete electrical lattice where the dynamics of modulated waves can be modeled by a generalized discrete nonlinear Schrödinger equation that interpolates between the Ablowitz-Ladik and discrete-self-trapping equations. Regions of modulational instability (MI) are investigated and experimentally, we observe that MI can develop even for continuous waves with frequencies higher than the linear cutoff frequency of the lattice. These results are confirmed by the observation of ‘‘staggered’’ localized modes. Experimentally, it is finally shown that unlike envelope solitons, which can be observed close to the zero-dispersion point, the staggered modes experience strong lattice effects.