An optical communication apparatus and printed circuit board (PCB), which include an optical interface for realizing concurrent read and write operations, and a data processing system including a memory module and the PCB are provided. The optical communication apparatus includes an optical interface unit configured to output optical signal of first data and receive optical signal of second data simultaneously, and an optical bus configured to transmit the optical signals between the first optical interface unit and a second optical interface unit, the second optical interface unit being configured to receive the optical signal of the first data and output the optical signal of the second data simultaneously. The optical signal of the first data and the optical signal of the second data have polarizations, respectively, orthogonal to each other.