Research On OCDMA-PON System And The Key Technologies

With the rapid development of new multimedia services, the entire communication network, especially the access network facing the enormous pressure as the bandwidth demand continues to grow, resulting the disadvantages in terms of bandwidth and security of the existing TDMA-based bandwidth sharing passive optical network technology become more and more prominent. So the new WDM based PON and OCDMA based PON have been proposed and carried out with in related experiments. With WDM-PON technology, every user exclusive a Independent wavelength. However, the limit of the wavelength resources and the complexity of the allocation of wavelength resources make it difficult to achieve large capacity and flexible user access. In contrast, OCDMA-PON has an excellent network security, information security and easy to implement large-capacity flexible user access, so that it is considered to be the best choice optical in the futuure optical access network.In this dissertation, the article researched the basic principle, system architecture and key technologies of the OCDMA-PON system. The paper's detailed work including:1.Summarized the development progress of the passive optical network,introduced OCDMA-PON system's advantages and current investigation status, and described the basic principle,system architecture and key technologies of the system.2.This dissertation focuses on the main key technologies of the OCDMA-PON such as the design of the optical OCDMA code, the encoding/decoding scheme, scheme of remodulation, the encryption technology, muti-modulation tech and so on. During the Comprehensive analysis of theory and simulation, we designed 127 Gold code as the optical address code and the time-domain spread spectrum phase encoding/decoding scheme,and also we raised the orthogonal remodulation tech based on DQPSK/OOK,DQPSK/PPM and and all-optical XOR encryption scheme based on SOA-MZI.3.OCDMA-PON simulation systems based on DQPSK/OOK and DQPSK/PPM were designed individually. In the same transmission condition,we simulated and analyse the Multi-User Interference, security and Receiver Sensitivity. After that, we studied the integration of OCDMA-PON and WDM-PON technology in future, that is the necessity and feasibility to realize WDM-OCDMA-PON.