The Study Of Multiple Access Interrupt In Optical Code Division Multiplexing Access System

There are many advantages in using code division multiple access (CDMA) techniques in optical fiber communication networks, which has a bright future in science field. Recently, OCDMA system have attracted many researchers' attention.Firstly, the basic theory and configuration of system is introduced, and the key technologies of OCDMA system is concluded, the present situation of study on OCDMA are also concluded. Then we introduce the pivotal techniques for OCDMA: research of address codes and design of encoder/decoder. Requirement of optical addressing codes, several kinds of addressing codes and realizing of all-optical encoder/decoder were introduced. And their advantage and disadvantage were compared either.Then, we took incoherent and asynchronous OCDMA as a study object, We study deeply on Multiple Access Interference and Bit Error Rate of OCDMA, in the first, we analyzed the system's Bit Error Rate formula in ideal transmission distortion of optical fiber, and several parameters' impact to Bit Error Rate was analyzed, and we proved that by modeling and simulation. Then combined with dispersion and no-linearity effect deteriorate the system performance, we put forward a upgraded BER equation and made a computer simulation to verify our conclusion.Finally, the measures of constricting multi-user interference were discussed, first of all, we analyzed I using optical hard-limiters to reduce multi-user interference and made a computer simulation to verify them. Then, combining multi-user detection technology in CDMA, we study theoretically on how to use that technology to reduce multi-user interference in OCDMA.