Exploring Propagation Dynamics Of Optical Soliton In One-Demension Optical Lattices

Spatial solitons are under intensive study these days due to their novel physics as well as potential applications. The study of dynamics of spatial solitons is of great im-portance both in theory and in practice. This thesis focuses on analysis and simulation of propagation dynamics of spatial solitons in new type optical lattices which can be fabricated by non-diffract. It includes following main parts:1.Asymmetrical surface soliton trainsThe existence, stability and propagation dynamics of multi-spot soliton packets in focusing saturable media was studied. Such solitons are supported by an interface beside which two harmonically photonic lattices with different modulation depths are imprinted. We show that the surface model can support stable higher-order structures in the form of asymmetrical surface soliton trains, which is in sharp contrast to ho-mogeneous media or uniform harmonic lattice modulations where stable asymmetrical multi-peaked solitons do not exist. Surface trains can be viewed as higher-order soliton states bound together by several different lowest order solitons with appropriate relative phases. Their existence as stable objects enriches the concept of compact manipulation of several different solitons as a single entity and offers an additional freedom to control the shape of solitons by adjusting the modulation depths beside the interface.2. Spatial solitons in linearly and nonlinearly amplitude-modulated optical latticesLinearly and nonlinearly amplitude-modulated (chirped) harmonic lattices can support odd and even solitons in both focusing and defocusing saturable media. The modulated lattice modifies the profiles and enlarges the stability domains of solitons, comparing with the unchirped one. Twisted solitons, or "soliton trains" whose pro-files exhibit multi-peak structures can also be supported by linearly and nonlinearly chirped lattices. In sharp contrast with periodic lattices, chirped lattices remarkably broaden the existence and stability domains of twisted solitons, especially for solitons with more components. While even solitons in focusing media and twisted solitons in defocusing media are unstable, odd and twisted solitons in focusing media are stable in relatively wide parameter windows. Chirped lattice can be used as a linear guidance to realize the oscillation of solitons which is impossible in unchirped lattice.3. Stable ring solitons in higher-order Bessel optical latticesIn this part, we provide existence, stability and propagation dynamics of ring soli-tons in a defocusing cubic nonlinear medium with an imprinted Bessel optical lattice. Various families of ring solitons with dark cores are found. We reveal that ring soli-tons could reside on different rings in different order Bessel lattices. The size of ring soliton is determined by the lattice ring where it resides. Such solitons can be made dynamically stable provided that the lattice is modulated deep enough. The uncovered phenomena may open a new way for soliton control and manipulation especially on the beams with relatively large dark cores.