Research On Optical Orthogonal Frequency Division Multiplexing Technology

Optical orthogonal frequency division multiplexing technology is a novel optical communication technology which combines electrical OFDM technology and optical fiber communication technology. It has high frequency efficiency, effective resistance to chromatic dispersion, polarization mode dispersion and non-linear effects. Recently, it has been the hot spot of the research in the field of hybrid broadband communication of light and wireless.In this thesis, some deep researches on the resistance capability of OOFDM to chromatic dispersion and polarization mode dispersion, and the methods to decrease the peak-to-average power ratio of the system are performed from two aspects of theory analysis and modeling simulation. The main work accomplished as follows:(1) The simulation platform of direct-detection-optical OFDM system is set up by OptiSystem and Matlab to analyze and simulate the resistance capability of OOFDM to chromatic dispersion and polarization mode dispersion in different rates system. And the simulation proves that compared with the transmission system without OOFDM, OOFDM can restrict the effects of chromatic dispersion and polarization mode dispersion, such as waveform distortion, rotation and contraction of planisphere. And meanwhile, it can increase the communication distance with OOFDM technology.(2) Based on the analysis on the reason that high PAPR occurs in OFDM system and some existed methods to decrease PAPR, a new method named MLCC-PTS is proposed. This method can simplify the generation process of candidate sequences by using of the relationship between candidate sequences, decrease the computational complexity largely, and improve the computational efficiency.(3) After analyzing the relationship between PAPR of OFDM signal and the value of the sum of self-correlation function of input data, and the deficiency of the reduction of PAPR only with IDFT and only PTS, a method of combining IDFT with PTS to decrease PAPR is proposed and simulated. The results turn out that IDFT-PTS can decrease PAPR more by 1.3 dB and 1dB compared with only PTS and only IDFT method, modifying the performance of PAPR further.