Nonlinear switching with a graphene coupler

We study nonlinear propagation of electromagnetic waves in two closely spaced graphene layers and demonstrate that this double-layer graphene waveguide can operate as an efficient nonlinear optical coupler for both continuous plasmons and for subwavelength spatial optical plasmon solitons. We analyze the nonlinearity-induced effects of light localization and symmetry breaking in such a graphene coupler, and predict that the interlayer power-dependent coupling provides a mechanism for optical beam control and manipulation at realistic input power levels.