Optical Code Division Multiple Access (ocdma) Compiled Research And Decoding System

Code-division multiple-access (CDMA) technique has been successfully used in satellite communication and mobile communication area, and it shows much more advantages than other communication techniques. Fiber communication is famous for its wide band width, but it has constraints of optical-electrical and electrical-optical transformation. So in order to make full use of the optical band width and provide more shared network channels for users, people invent optical-code-division multiple-access (OCDMA) technique. And OCDMA is getting more and more attention for its good attributes as high security, soft capacity, asynchronous access, convenient network management, etc. and it has huge potential in communication area.This thesis mainly discussed the realization and performance of all the OCDMA encode-decode system elements after the introduction to the CODMA key techniques. The main contents are outlined as follows:1. Summarize the development and recent research achievements of OCDMA as well as its advantages.2. List and analyze the key techniques of OCDMA system, including design of address codes, realization of coder and decoder, optical thresholder, etc.3. Analyze the setup of OCDMA system and some system solutions, which have different bit rates and coding methods, are raised.1) A 155Mbps, bidirectional demo system of OCDMA video transmission. (One user, two-dimensional wavelength-time coding.)2) A 2.5Gbps, one-dimensional phase encoded OCDMA system using equivalent phase shift fiber Bragg grating.4. Analyze the performance of receiving part of OCDMA system, and eliminate the noise of received signal to get rid of multiple-user-interference (MUI) using optical thresholder.5. Introduce some application prospects of OCDMA techniques, and some more coding methods.