Abstract
Optical parallel logic operation is performed on the interference fringe shifted corresponding to the optical input. In the spatial light modulator, the optical input induces the refractive-index change which results in the shift of the fringe formed with the readout beam. The multiple-output scheme of logic gates is achieved by spatially dividing the output fringe. The multiple-valued logic is also implemented by adjusting the phase change for the multiple level of the optical input. Moreover, complementary logic pairs are always simultaneously provided when this method is used.