| With the explosive growth in bandwidth demand in networks which is driven by video applications, there has increasing demand for higher bandwidth and more reliable data and voice services. Therefore, it has become necessary to develop novel techniques and modulation formats that are both spectrally efficient and resilient to fiber impairments. Optical orthogonal frequency division multiplexing(OFDM) is an attractive candidate for future high capacity optical transmission systems, due to its high spectral efficiency and resilience to fiber dispersion. Besides, the reaserch on optical OFDM based on DSP technology has been developed in recent years.In this paper, a simple and novel design of real-time OFDM system is realized and analyzed. The mainly achievements as the following:(1)The in-depth studies on OFDM are done in the second cahpter, including its math model, structure components, preparing for forther signal modulation. Also based on the current status of optical network, the advantage of real-time OFDM is analyzed.(2)Based on the above study of OFDM, novel OFDM signal transmitter is realized in chapter 3. Currently, most of domestic experiments about optical OFDM are still on off-line process level. While, using the Xilinx Virtex 5 board, a high speed signal transmitter is realized, which can achieve on-line processing. The generated signal is modulated in advanced 16 QAM method. Compared with the off-line process equipments, it cost lower which is benefit to commertial.(3)The 2.5 Gb/s real-time optical OFDM network is designed and the transmition performent is simulated, including transmit rate, transmit length and subcarrier. Simulation results show that the proposed scheme achieved best which provide 1024 FFT; 512 subcarriers, 1km fiber length. |
