Research On The Key Technologies Of Optical Orthogonal Frequency Division Multiplexing And The Simulaton System Performance

Nowadays, as the level of social information and the new internet data services continuously rising up, greater demands of transmission bandwidth and efficiency are being placed by exponential growth of the mass flow of digital information. Orthogonal Frequency Division Multiplexing(OFDM) technology used in optical fiber communication is one of the important alternative routes to enchance the communication transmission spectrum efficiency. The combination of coherent detection and OFDM not only promote the development of ultra-high spectral efficiency of optical communication,but also may provide a unique bandwidth management potential for further optical network. The coherent optical orthogonal frequency division multiplexing(CO-OFDM) technology has its own unique advanges in the future reconfigurable optical networks. Therefore, various countries have already launched a study to explore the related work. Based on this, this article has mainly researched on receiver key module algorithms and transmission performance of Multiple Input Multiple Output(MIMO) CO-OFDM system.Firstly, based on the window synchronization, the Constant Amplitude Zero Auto Correlation(CAZAC) sequence has been discussed as training sequence. It can be found that compared to the other methods, the CAZAC sequences can improve the performance of the window synchronization. And then carrier frequency offset estimation algorithm was discussed.Channel estimation algorithms based on time domain averaging and frequency domain averaging have been simulated and analyzed in order to estimate the system chromatic dispersion and polarization mode dispersion. What's more, system overhead and enhanced performance results have also been analyzed under different optical signal to noise ratio, algorithm parameters and signal damage. We compared the performance when different training symbols and algorithms were used to estimate the polarization mode dispersion. In phase noise estimation module, the simulation mode added the pilot to estimate. The simulation results showed that the system can meet the need of the demand.Finally, the MIMO-CO-OFDM system simulation model has been designed and simulated. Within the framework of receiver digital signal processing algorithms, we used the window synchronization and carrier frequency offset estimation algorithm based CAZAC sequence. Frequency domain averaging channel estimation algorithm using training sequence and phase noise estimation algorithm based on pilot were intergraded in the framework. Based on the proposed system simulation model, we have analysised the receiver bit error ratio performance in allusion to laser linewidth, optical signal to noise ratio, differential group delay dispersion as well as chromatic dispersion. Meanwhile, channel estimation module window length has been optimized towards fiber link parameters. We have also simulated the optical signal to noise ratio penalty cased by chromatic dispersion as well as the laser linewidth.The simulation model and calculation results presented by this artical has a certain reference value for orthogonal frequency division multiplexed optical communication.