Defining elements with reconfigurable input-output characteristics is of importance to achieve flexible circuitry where light can be manipulated and routed using external control signals. We have developed an experimental approach for shaping of the transmission function of multimode silicon photonic waveguides by projecting a pattern of local nonlinear perturbations induced by an ultrafast laser pulse. Making use of the degrees of freedom offered by a spatial light modulator, the technique offers a new approach for studying light transport, for controlling its flow on ultrafast time scale, and for programming functions on a photonic chip.
