Compensation Of Dispersion And Nonlinear Impairments In Optical OFDM System Using Backpropagation

Optical orthogonal frequency division multiplexing system (OOFDM) is based on opticalcommunications and wireless technologies. This technology can improve spectrum efficiency, inthe ultra-long and ultra-high rate transmission system, this technology has transcendenceadvantage. Optical system can not avoid the dispersion effect and nonlinear effect, so, somemethod should be used to compensate for the dispersion and nonlinear effect of the optical fibercommunications in the receive part. However, most of the existing compensation technologiesare ignore the nonlinear damage, only compensate for the dispersion or ignore the dispersion,only compensate for nonlinear damage. The technology to compensate for dispersion andnonlinear damage at the same time is still immature. This paper use back-propagation tocompensation the dispersion and nonlinear damage in the optical orthogonal frequency divisionmultiplexing system at the same time.By reading a lot of literature and basing on existing theory, this paper usedback-propagation to compensation dispersion and nonlinear damage in the optical orthogonalfrequency division multiplexing system. The main work and the results of this paper as followed:Firstly, this paper analyzes the theoretical basis of optical OFDM system and theSchr?dinger equation when optical transmission in optical fiber, and then summarize thecharacteristics of dispersion and nonlinear damage in the optical OFDM system and give theprecise model of dispersion and nonlinear damage in this communication system.Secondly, based on the VPI platform, design optical orthogonal frequency divisionmultiplexing system, use QAM to modulation this system; analyze the constellation of thereceive signals to improve that in the data receiving part of optical OFDM system, thecompensation for dispersive and nonlinear damage is still be needed.Thirdly, use back-propagation to compensation the dispersive and nonlinear damage ofoptical OFDM system, and then compared and analyzed the vary of constellations beforecompensation and after.The results of simulation show that using back-propagation to compensation thedispersion and nonlinear damage has very good results. Compare with the other compensations,the method in this paper can compensation the dispersion and nonlinear damage at the same time.