Research On Forward Error Correction Technique In High-speed Fiber Optical Communication Systems

In high speed and polarization-mode dispersion(PMD) limited fiber optic communication systems,PMD will expanse the pulse , induce high bit error rate(BER) and terribly disturb the transmission property. In this dissertation, forward error correction(FEC) technique is used to combat the performance of PMD.By adding some redundant bits in transmission and decoding at the receiver, the BER will greatly reduced and the transmission property will enhanced a lot. At the same time,the single-channel PMD compensation technique is also added to the system, then a numerical simulation is listed to show the improvement of the transmission effect. In addition, the simulation based on PMD compensation of some formats:such as return zero format (RZ) with 50% duty cycle, carrier suppressed RZ format(CSRZ) and return to zero format(NRZ) in a single-channel system is given,and the greatest scheme can be received.The research works in the dissertation are summarized as follows:The basic concepts of FEC and different coding technique are introduced briefly,while the knowlodge of the RS is mainly discussed.The basic concepts of PMD, their numerical models used as emulation, the distribution of the first- and higher-order PMD and compensation schemes are reviewed and summarized compendiously.In PMD limited systems, the signal received with or without FEC are compared, and the tranmission simulation is given to show the effect of adding FEC to the systems.The simulation based on PMD compensation of some new-style formats such as return zero format (RZ) with 50% duty cycle respectively, carrier suppressed RZ format(CSRZ) and return to zero format(NRZ) in a single-channel system is given.Combine FEC and compensation technique in PMD limited systems to see how the combination can improve the PMD tolerance by see the relationship between the DGD and Q value,then...