ptical code division multiple access (OCDMA) system is one of the most competitive multiplexing technologies and will be widely applied in the field of optical communication. The scheme fiber-optical OCDMA system was analyzed in details. The strategies in the designing of encoder/decoder were compared and evaluated. Especially, the encoder/decoders based on fiber Bragg-grating and arrayed guide grating are discussed. The future application of OCDMA in the field of optical communication is predicted.