We propose a new type of optical fiber called homogeneous multi-core fiber (MCF) to drastically increase the transmission capacity of single fiber using the mode-division multiplexing. In this MCF, identical cores are closely arranged so that the cores are strongly coupled to each other to form coupled modes, each of which corresponds to a transmission channel. A novel mode multi/demultiplexer is proposed to discriminate each coupled mode. To rearrange cores to match the mode multi/demultiplexer, a hybrid configuration of coupled homogeneous with uncoupled heterogeneous multi-core is proposed. An example of hybrid configuration is designed so that the cross-talk becomes sufficiently small.