The Study On Transmission Characteristics Of High-speed Optical Fiber Communication System

With the information explosion, the requirement of speed and bandwidth are more serious and urgent. Up to now, the large capacity and long-haul optical fiber communication technologies have been rapidly developed. The 40Gb/s high speed optical fiber communication transmission system is becoming one of hottest topic recently. The follow technologies are the key issue for 40Gb/s high speed optical fiber communication transmission system:①Low noises and wide bandwidth optical amplifier;②High speed FEC technology;③Efficient MUX/DEMUX technology;④The signal modulation formats with higher optical noises, nonlinear effect tolerance and higher spectral efficiency.Sponsored by national 863 projects and Wuhan technology innovation project, the 40Gb/s high-speed optical fiber communication transmission system is comprehensive investigated in this thesis. The main achievements and conclusions are listed as follows:(1) Researches on 40Gb/s high-speed optical fiber communication transmission system and its last developments are reviewed; the meaning of choosing optical signal modulation formats is discussed.(2) Introducing the Mach-Zender modulator (MZM) and electronic-absorb modulator (EAM)'s goods and flaws. Based the theoretical analysis models of MZM, the theoretical express of NRZ, RZ, CS-RZ and the DPSK modulation formats are given. The spectrums of these modulation formats are analyzed. Numerical simulations of these modulation signals are done with the Matlab software, and get the spectrums via Fourierism transform method. The numerical simulation results are accord with theoretical analysis.(3) The stimulated transmitter models of these optical signal modulations formats are established via Optisystem software. Their waveforms, eye diagrams, and spectrums are stimulated; the results are accord with the others. When the dispersion compensate fiber locations is fixed in the middle, different SMF distance ratios stimulations experiments are done. The result shows that the symmetry dispersion management map has the best transimision performance. The experiments stimulations of back to back, dispersion tolerance and different dispersion management with different modulations are done, and the longest distance of different dispersion managements are compared. (4)The experiments of back to back, long-haul transmission, dispersion tolerance and different distance ratio with different modulation signals are carried out. It is shows that the CS-RZ modulation has the best transmission performances; NRZ modulation has the biggest dispersion tolerance.