This paper gives the background of the opitical code division multiple access(OCDMA) technology

compares its techniques with each other and sets forth the advantages. OCDMA features that it is asynchronous in time and frequency field

and does not need signal synchronization; it uses the same one central wave

and does not need wave-controlling; it has soft capacity and good security; it also can use optical fiber bandwidth sufficiently. The key techniques are depicted in detail on the basis of the fundament of optical code division multiple access. Finally

its applications are examined. DCDMA can realize real-time operation and free access when used in multi-media communications. Its protocol of media access is simple

overcoming "electron bottle-neck effect"

therefore data-transmitting rate can reach the order of Tb/s when used in high-speed computer local area networks. In communication network

it is another option for multiplexing. In optical fiber access network

it can overcome conventional synchronization problem. When used in HFC network

it can also solve up-link bandwidth problem and release dual-direction communication. In CATV and VOD service

it can realize changing and dual-direction service. Therefore

the technique of optical code division multiple access can find wide applications in the future.