Coherent Coupling Of Spatial Optical Solitons In Centrosymmetric Photorefractive Crystals

Photorefractive spatial solitons, which refer to maintain the same shape of theoptical beams propagating in the photorefractive media, are a nonlinear opticalphenomena and the result of diffraction balanced the photorefractive effect. For themerits of low optical power, long storage time, beams mutual control and so on,photorefractive spatial solitons are prospective in optical integration, opticalconnection, and optical information processing. In this dissertation, the coherentcoupling phenomena of the spatial optical solitons propagating along the same line inthe centrosymmetric photorefractive crystals are investigate theoretically.The evolution of the two coherent coupling optical beams propagating in thesame line in the centrosymmetric photorefractive crystals based on the Kukhtarevmodel. The solving processes of the coherent coupling bright-bright soliton pairs anddark-dark soliton pairs are described, and the required conditions of the the coherentcoupling bright-bright and dark-dark soliton pairs in the centrosymmetricphotorefractive crystals are got. The effects of the externally applied electric fieldand the phase of the two optical beam as well as the intensity ratio on the solitonpairs. The curves of the intensity and width of the coherent coupled bright-bright anddark-dark solitons pairs are obtained by use of numerical integration procedures,corresponding examples where the centrosymmetric photorefractive crystals aretaken to be KLTN with the suitable crystal parameters.The evolution equation of the coherent coupling low-amplitude spatial solitonsin the centrosymmetric photorefractive crystals is developed, when the externallyapplied electric fields are considered. The explicit expressions of the coherentcoupling low-amplitude bright-bright and dark-dark soliton pairs are obtained, andthe expressions of the width the low-amplitude soliton pairs. The required conditionsof the the coherent coupling low-amplitude bright-bright and dark-dark soliton pairsin the centrosymmetric photorefractive crystals are got. The curves of the intensityand width of the coherent coupled low-amplitude bright-bright and dark-darksolitons pairs are obtained by use of numerical integration procedures, correspondingexamples where the centrosymmetric photorefractive crystals are taken to be KLTN with the suitable crystal parameters.By the use of the equations of the dielectric constant and the dark irradianceversus temperature, the evolution of the two coherent coupling optical beamspropagating in the same line in the centrosymmetric photorefractive crystals aredesired, under the condition of temperature. The solving processes of the coherentcoupling bright-bright and dark-dark soliton pairs, and the explicit expressions of thecoherent coupling low-amplitude bright-bright and dark-dark soliton pairs are desired.The curves of the intensity and width of the coherent coupled bright-bright anddark-dark solitons pairs are obtained by use of numerical integration procedures,corresponding examples where the centrosymmetric photorefractive crystals aretaken to be KLTN, on the condition of the different outside temperature, phase andexternally applied electric field.