Based On Two Key Technologies In Ocdm Optical Network

OCDMA is an integration of CDMA and optical fiber communication. It offers several unique advantages, such as strong resistance against interference, asynchronous accessing, convenient management, strong security performance and so on. Due to the user's data is coded and decoded by all-optical signal processing, OCDM is regarded as a most promising technology to relize all-optical communication. This paper presents theoretical research on OADM and OPS based on OCDM technology.The main contents are given as following:(1) Optical hard limiter is introduced into the structure of OADM base on OCDM. The code drop unit in OCDM ring networks is analyzed. Expressions of BER performance of every user are obtained by using Markov Chain model and state transition probability matrix. The results show that even though code drop unit removes the code effectively from the ring network, it will deteriorate the BER performance of other users. The relation between BER performance and code length, code weight is analyzed in detail. After that, we propose an OCDM ring network access control method which can improve the network's BER performance by BER monitoring and feedback, with chip time control and codes random selection. Simulation result shows that the method can efficiently improve the BER performance of users in the OCDM ring network.(2) An OPS system model is introduced. The generation method, correlation, correlation distribution and coder/decoder of 4-phase OCDM codes are studied. The performance of interference between optical packets is analyzed. The performance of systems based on 4-phase OCDM with code length 127 and 63is simulated. The result shows that 4-phase OCDM codes is regards as a better label in OPS based on OCDM.