| Summary: | We theoretically investigate light propagation in two coupled nonlinear waveguides with a certain static propagation constant detuning between two waveguides and with the linear refractive index modulated along the propagation direction. By slowly varying the amplitude of modulation, we steer the light to the desired output waveguide when equal amounts of lights are launched into each waveguide. We reveal that depending on the sign of the static propagation constant mismatch (detuning) between two waveguides, the launched light can be completely switched to either of waveguides. Additionally, we numerically examine the performances of light switching for general inputs and modulation amplitudes, and show that the localization of output light is robust against small to moderate variations in the final modulation amplitude, phase difference and intensity distribution of input field between two waveguides. More importantly, according to the principle of the proposed scheme, we are capable of steering the output light to the targeted waveguide at extremely low input power. In theory, our findings can be explained qualitatively by means of adiabatic navigation of the so-called nonlinear Floquet states. Keywords: Light tunneling, Adiabatic passage, Nonlinear waveguides
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