| Today, the technology of optical-soliton communication is the long distance communication, and it becomes the preferable scheme of new generation of the rapid velocity and long distance. It accomplishes stability transmission by what strong pulse products nonlinear suppression compensating broadening of pulse-dispersion in optical fiber. It has become an excellent scheme in the high rate and long-haul optical communications of the next generation. However, with the increase in the number of multiplexed channels and bit-rate, the pulse width is getting narrower and narrower up to picosecond (PS) or femtosecond (FS) duration pulse to carry message. On the one hand, soliton self-frequency shift (SSFS) and bandwidths induced by intrapulse Raman scattering (IRS) vary rapidly with their durations and transmission distances, and on the other hand, their timing jitter originating from third-order dispersion and soliton interaction, IRS and self-steepening will increase greatly. Both of them have become the dominating limitation factors of soliton system. With the application of WDM in optical-soliton communication, the bit rate and relay distance is also increasing. With the improvement of speed, some factors ignored in the low-speed optical communication system have to be noticed now. The factors affecting the capability of ultrahigh-speed optical communication system are analyzed and studied in this paper, and some plans are devised and discussed to restrain the factors.Combining theory with practice and according to experience in work and theory analysis in reference materials, this paper summarize the relevant nonlinearities effects in the high speed and ultra-long-haul WDM communications system. It reviews the high speed and ultra long haul WDM communication system's developing process, and analyzes a variety of challenges such as singal loss, dispersion and nonlinearities effects in the process.In this paper, Nonlinear Schrodinger equation is solved by the use of the variational approach under the condition of the multi-channel higher-order effects and soliton interaction and the evolution properties of the chirping Gaussian quasi-soliton pulse and SSFS is revealed in the WDM system. The relation between the construction parameters and the stability of the system is investigated and a stable operation condition is revealed. We discover that in the presence of SSFS, by using the combined control method of up-frequency guiding filtering and amplitude modulation, the stable transmission of the chirping Gaussian quasi-soliton pulses with zero frequency shift at bit rates up to 160Gbit/s and above can be realized. |
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