Performance Analysis Of High Speed DWDM-PON System

The growing broadband access networks made higher demands to fiber-optic access technology. Passive Optical Network Driven (PON) technology is just rapidly developing with the development of the Fiber-to-the-Home (FTTH) technology. As a leader in PON, DWDM-PON system on behalf of the future direction of FTTH development has the study of great significance. During the process of DWDM-PON technology popularity, it faced many key issues, such as quality decline brought about by high-speed communications, as well as higher system costs. In this paper, starting from the above two points, focusing on analysis of a variety of modulation formats at high speed (40Gb/s) DWDM transmission system performance, and then the design a 16-channel DWDM system using the re-modulation mode, and with the performance analysis.First of all, through the 40Gb/s of DWDM transmission systems simulation studies, carried out the comparison of NRZ, RZ, CSRZ and RZ-DPSK, CSRZ-DPSK modulation with performance detail analysis. Results show that, CSRZ spectrum width was just between NRZ and RZ. It not only had the high dispersion tolerance, and also had stronger resistance to nonlinear optical effects, such as SPM, FWM. It was the best choice of the three above. And among the DPSK modulation modes, witch had obvious better performance, CSRZ-DPSK modulation signal was better. While its peak value of Q-factor is slightly lower than RZ-DPSK signal, but it had many significant advantages, such as tolerance to higher fiber optical input power, the better balance of channels performance, and its narrow light spectrum width. Taking all these advantages, CSRZ-DPSK modulation signal was very suitable for high-speed dense wavelength division multiplexing passive optical network applications.The second half of this paper was focusing on WDM-PON design with considerations of client device cost reduction. Using the light loop-back technology, designed and simulated 40Gb/s 16 channels CSRZ-DPSK modulated DWDM systems, The upstream signal was generated by re-modulation of the downstream DPSK signal. The system overcame the negative impact of 40Gb/s high-speed transmission, and reduced the client device cost of light sources simultaneously. It fit the requirements of next-generation broadband access technology, and would be a competitive solution for the provision of FTTH in China.