The Study Of The Self-Bending And Interactions Of Spatical Solitons In Photorefractive Crystal

Photorefractibe spatial solitons can be formed when the diffraction of the beam is exactlybalanced by self-focusing due to the photorefractive material nonlinearity at mW power levels.They have been attracted researchers’ considerable interest by their potential application inall-optical, optical waveguide and optical communications fields. This thesis mainly describesresearch on the self-bending and interactions of photorefractive spatial screening solitons. Therelated works and results are shown below.1. Review the history background of the research of spatial solitons in photorefractivecrystal, and introduce the respective mechanism of three types of the PR spatial solitons underthe steady-state.2. Theoretically infer the mathematic expression of the space charge field inphotorefractive crystal by the photorefractive effect. And then get the normolized dynamicevolution equation and give the steaty-state bright soliton numerical solution and full-widthhalf-maximun(FWHM) of the intensity.3. The features of the self-deflection of the screening-photorefractive spatial soliton areinvestigated. By considering the diffusion effect, the influence of first-order and higher-orderspace charge field on the propagation characteristics both on the theory and numerical simulationaspects. The results show that the center of the optical beam moves on a parabolic trajectory; Asto the highter-order space charge field, the self-bending process is further enhanced by a factorthat varies cubically with the applied field. In addition, by taking into accont the temperaturedependence of the diffusion effect and the dark irradiance, the influnce of temperature on theself-deflection feature of the screening-photorefrative spatial soliton is researched. Thenumerical study shows that the bending distance of the soliton beam center increase, reaching itsmaximum value at the characteristic temperature.4. Numerical investigations of the screening-photorefractive spatial solitons interaction.The influnces of initial phase differnce, the intensity and peak separation on the interactionsbetween screening bright solitons are investigated. Furthermore, the influnces of the diffusion effect on the solitons interaction are also discussed. The results show that the in-phase interactionwill result in the separation of two solitons from each other; As for the anti-phase interaction side,two solitons separated each other and delect simultaneously to the same side. Finally,interactions among multiple solitons are also investigated.5. Give a simple introduction of the theory of the holographic solitons and its thenormolized dynamic evolution equation. And show the holographic soliton numerical solutionand full-width half-maximun(FWHM) of the intensity.