Propagation Characteristic Of Soliton And Switching Behavior Of Soliton In Periodic Lattices

Due to the advantages in the optical communication and AON construction,more and more attention has been paid to the optical soliton research.Among them,the propagation characteristics of optical soliton in the medium are particularly important.Through researches in this area, people can more clearly recognize the pros and cons in the process of optical soliton propagation and the various influencing factors,which could be taken advantage of the optical soliton manipulation.On the other hand,in optical soliton communication systems,soliton devices are an essential component. Through the design of optical soliton devices,strong technical support can be provided to optical soliton communication system construction.In this thesis, using the numerical simulation methods,the propagation characteristics and the switching behavior of optical soliton in the homogeneous medium and the periodic lattices are discussed,separately.Moreover,two multiple periods lattices systems are proposed and some new meaningful results are arrived.According to the soliton theory,nonlinear Schrodinger(NLS) equation to describe the propagation of soliton in the homogeneous medium is numerically researched by split-step Fourier transform method(SSFM).In the homogeneous medium,the effect of high-order dispersion on propagation of optical soliton and the distinct phenomenon which are came from the launching of different soliton pulse pairs are discussed,respectively.The result shows that the soliton propagates smoothly if the high-order dispersion effect does no be considered,but the oscillation is found obviously and it is correlative with the parity of the dispersion order at the case of the high-order dispersion effect.If including three-order dispersion effect,when a couple of soliton pulses is launched into the lattice,then by altering the phase difference of the soliton pair,the single-side-oscillation will be changed dramaticlly by the three-order dispersion and the their energy can transfer each other.Furthermore,two optical lattices with Kerr-type nonlinear medium with the modulation of multiple periods were proposed.The switch characteristics of soliton in these lattices are studied and compared with that of the single period optical lattices.First of all,in the two multiple periodic lattices,the stability of energy of the soliton pulse are numerically analyzed as the soliton pulse launched at a certain initial angle.The numbers of the channel in which was traversed by soliton pulse are numerically calculated before the soliton pulse is trapped in the lattices channel,and it is compared with that of the situation of the single period optical lattices.Then,the difference between channels number of soliton localization within the same energy region is compared,and also does the response time of the stability of soliton in same traversing channel.And came to the conclusion,the two multiple periods optical lattices proposed is superior to the single periods optical lattices in terms of the soliton switch effect.Especially the two multiple periods optical lattices may have very good prospects and application for designing of optical soliton switch component.