A sawtooth resonant-cavity-coupled metal-waveguide structure is proposed. It is found that adding a sawtooth resonator improves the signal output frequency of the waveguide structure. In addition, the output signal frequency of the logic-gate light source can be controlled by adjusting the length and width of the sawtooth resonator. Moreover, the increase of logic signal output ports by increasing the number of output waveguides can help to realize the two- and three-channel signal outputs. This logic gate output light source, constructed by coupling a sawtooth resonator with a metal waveguide structure, has a broad working bandwidth and a high transmission efficiency. With a suitable adjustment of the length and width of the sawtooth resonator one can get a transmission efficiency of 60% and an average working range of 1000 nm.