The propagation of chemical waves in the model of the light-catalyzed Belousov-Zhabotinsky (BZ) reaction with asymmetric illumination has been studied numerically in a one-dimensional environment. The asymmetric distribution of light intensity is sufficient to yield unidirectional wave propagation in wide parametric domains. Depending on the excitability and the diffusion coefficient of the catalyst. two types of chemical diode exist with opposite directionality.