Research Of Different Categories Of Electronic Dispersion Compensation

In high bit rate (10G bit/s and beyond) WDM optical transmission systems, the maximum link length that can be covered without the need for signal regeneration is limited by chromatic dispersion (CD) and polarization mode dispersion (PMD) in single mode optical fiber. This will cause optical pulse broadening and finally cause inter-symbol-interfere. So some solutions (optical, electronic) for overcoming the limitation have been proposed in the optical system.Traditional dispersion compensation module adopts the passive optical components. These methods use lots of expensive and bulky optical elements to do the inverse effects of the dispersion on the transmitted signal. Though this method works, but comparing with Electronic Dispersion Compensation, they have many disadvantages such as the less adaptability. As a new technology for fiber dispersion compensation, Electronic Dispersion Compensation (EDC) is gradually being applied in practical projects.Compensator is the primary component of EDC. FFE and DFE are commonly used. A simulation is done in an optical system with 10G bits/s and OOK modulation. The suitable FFE and DFE architecture is given by the simulation results in this situation.Compareance is done between EDC-TX and EDC-RX. And the results show that the performance of EDC-TX is better than EDC-RX. And this superiority is more and more when the fiber length is longer and longer.Some advanced modulations like ODB can enhance the length of transmission distance of optical system. But these modulations can also influence the performance of EDC. The performance of EDC adopts DFE is simulated in 10Gbits/s ODB optical system. The result shows that: the ODB format reduces the performance of EDC for compensatingthe PMD and CD.For ODB modulation, a compact nonlinear equalizer is received, and the simulation results show that the performance is acceptable compare with the common nonlinear equalizer in the past reference.