Characteristic Study Of The Optical Soliton Propagating In The Fiber

Applications of optical fiber are focus on two respects, one is photoelectricity measurement and optical fiber sensing, the other is used in the optical fiber communication. Along with the requirement of continually improving large capacity and high speed communication, optical soliton communication turn into research hotspot of the scientists from different countries. The optical soliton is a kind of optical pulse train, it can keep shape while propagating in the fiber for a long distance. And this character is the base of realizing optical soliton communication. The soliton can transmit stably in the fiber attributes to the balance of the group velocity dispersion(GVD) and self phase modulation(SPM). But the practical optical fiber communication is not perfect, there are two main influence elements, one is arose by the fiber, such as waste, GVD and polarization mode dispersion(PMD) etal.. The other is arose by the nonlinear interactions, such as SPM, cross phase modulation(XPM), four wave mixing etal.. So studying on the transmitting character of the optical soliton has important significance to system design and practical realization. The thesis has done several respects work on the characters of the soliton propagating in the fiber and soliton experimental system as below:Firstly, based on Maxwell basic theory, the nonlinear Schr?dinger equation (NLSE) is deduced, and it is modified to obtain the high order modified NLSE. Using PMD basic theory and the notation, the coupled NLSE of soliton in birefringent fiber is deduced. The characters of the picosecond(ps) soliton propagating in the fiber are studied and numerically simulated, and the soliton decay is discovered by researching on the interactions of high order solitons, the decay rule of the pulse propagating in the fiber is obtained. High order dispersion can induce more serious split of high order solitons, the two splitting waves will rapidly superposed each other, and it will bring disadvantageous influence to the communication.Using HNLSE, the influence of the second order dispersion coefficient to the third order femtosecond(fs) soliton propagating is mainly analyzed. The split of third order soliton will be controlled when the second order dispersion coefficient become bigger, it puts up narrow spectrum in the frequency field. The effects of self steeping, selffrequency shift parameter for second order soliton are also analyzed. It points out that in a range of the parameters, the self frequency shift effect is bigger than the self steeping effect, it is a primary effect in the soliton propagation of fs width, and it can restrain the self frequency shift effect in a certain extent.Synchronous modulation technology is studied to compensate the PMD of the classical soliton system, and the maximum propagation distance is geminated increasing and the propagation quality is effectively enhanced. Sliding-frequency filter restrains the PMD diminutively in the classical soliton system but restrains the PMD distinctly in the DMS system. The filter controlling the propagation characters in birefringent fiber of the DMS is researched and the variation method is introduced to analyze the rule of the DMS. The result indicates that filter control of the PMD clearly optimizes the propagation capability of the DMS.The DFB-LD is experimentally studied and the fiber grating filter is used to eliminate the initial chirp of the pulse, and the transform limited pulses are obtained. The experiment system is constructed and the ps soliton propagating 34km without aberrance is realized.