All optical comparators play crucial roles in all optical data processing systems. In this paper we proposed a novel structure for realizing an all optical comparator, which can compares two 1-bit binary codes. For this purpose we used 4 nonlinear resonant rings. The final structure has two input –namely X and Y_ and three output ports –namely F1, F2 and F3-. The maximum time delay of the proposed structure is about 6 ps. The results show that, when X and Y are the same, only F3 is ON, when X is ON and Y is OFF, only F1 is ON and finally when Y is ON and X is OFF, only F2 is ON.