Polarization mode dispersion (PMD) is one of the major obstacles in high-speed (above 100 Gbits rate) and long-haul optical communication system. In order to meet the requirements of high-sped optical communication quality, some PMD compensation and mitigation schemes had been developed. Forward error correction (FEC) is useful to increasing the system margin. The combination of distributed fast polarization scrambler (D-FPS) and FEC is an effective method to improving the optical system's PMD tolerance. The fundamental reason is that D-FPS can accelerate the redistribution of the link PMD to enable FEC to be more effective during the periods that would otherwise have PMD outages. Another advantage of this scheme is that it can mitigate the influence of PMD in multichannel system without feedback control and compensation based on each channel. The principle and performance of scrambling is introduced in this paper and the fundamental idea of improving PMD mitigation by using D-FPS combined with FEC is proposed. Some key factors such as scrambling speed and the number of scrambler which affecting the performance of this scheme are also introduced. Finally, proposing an assumption that the impact for system performance caused by the style of FPSs is distributed along the fiber link, and the mathematical estimation model is established. The combination of D-FPS and FEC would be a promising approach for performance improvement in ultra-high-speed optical communication system.© (2010) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.