  We employ the process of non-degenerate four-wave mixing Bragg scattering
(FWM-BS) to demonstrate all-optical control in a silicon platform. In our
configuration, a strong, non-information-carrying pump is mixed with a weak
control pump and an input signal in a silicon-on-insulator waveguide. Through
the optical nonlinearity of this highly-confining waveguide, the weak pump
controls the wavelength conversion process from the signal to an idler, leading
to a controlled depletion of the signal. The strong pump, on the other hand,
plays the role of a constant bias. In this work, we show experimentally that it
is possible to implement this low-power switching technique as a first step
towards universal optical logic gates, and test the performance with random
binary data. Even at very low powers, where the signal and control pump levels
are almost equal, the eye-diagrams remain open, indicating a successful
operation of the logic gates.
