Study On The Optical Soliton Transmission Characteristics

The paper has researched the transmission characteristics of solitons. Time solitons and spatial solitons have been studied. Researching for time solitons has theoretical and practical significance for designing and implementing high-speed optical solitons communication. Spatial optical solitons have the potential applications in all-optical switching, optical waveguide, optical display, optical computing, etc. At the same time,the spatial optical solitons also have the important significance in related theoretical researching and validation of physicsWhen researched the time solitons, A form of symmetric split-step Fourier method is carefully discussed. Researched the influence of third-order dispersion on state-ground solitons transmission, found the state-ground solitons pulse will be distorted by the third-order dispersion. The case of researching the two high-order solitons are less, We have studied the interaction between two high-order solitons, found that the transmission characteristics of the two second-order solitons and the two third-order solitons are significantly different from the two first-order solitons, the two second-order solitons and the two third-order solitons will not attract and collide periodically, the interaction between the two second-order solitons and the two third-order solitons will periodically produce ramification solitons in the middle, in same transmission distance, the third-order soliton-pair produce more derivative solitons than the second-order soliton-pair.When researched gap solitons in optical lattices, get the blouch band structures of one-dimensional and two-dimensional lattices both by the plane wave expansion method. To calculate the numerical gap solitons solution of one-dimension optical lattices, used the shooting method, and used The modified squared-operator method to calulate the numerical gap solitons solution of two-dimension optical lattices. When simulated spatial optical solitons transmit, used symmetric split-step Fourier method.The paper has researched gap solitons in superlattice, the propagation characteristics of these solitons were carefully discussed. It is found that these gap solitons only transmit stably in low power region.Gap solitons in two-demensional square lattices in focusing saturable nonlinearity have been researshed, we constructed a defect in the square lattices. It is found that for the negative defect, the defect gap solitons not only exist in the semi-infinite gap, but also exist in the first gap, increasing the defect depth, the stable region only in the moderate power region in the first gap; In the semi-infinite gap, with the increasing of defect depth, defect solitons will unstably transmit in the entire gap. Forpositive defect, gap solitons only exist in semi-infinite gap, and these solitons only can stably transmit in low power region and unstably transmit in high power region. The paper also has researshed the defect gap solitons in triangular optical lattices.For the negative defect, solitons only exist in semi-infinite gap, and it can stably transmit only in the lower power region. For the negative defect, solitons not only exist in the semi-infinte gap, but also exist in the first gap, with the increasing of thedefect depth, the solitons will unstable in the whole semi-infinte gap, and in the first gap, it will be unstable in lower power region, high power region and lower power region, untill the whole first gap region.Finally, the paper has researched the gap solitons'stability in kerr nonlinearity, it is found that in the semi-infinite gap, vortex and discrete solitons near the band can not stably transmit.