An efficient technique for controlling the spatial bright soliton emission from a nonlinear waveguide is demonstrated numerically for what is to our knowledge the first time. The principle of this technique is based on the addition of a weak antisymmetric signal as a probe, the control parameters being the amplitude and the phase of the probe. A novel nonlinear device, the three-waveguide soliton coupler, is introduced and discussed as an application. © 1994 Optical Society of America.