共查询到18条相似文献,搜索用时 171 毫秒
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研究了非相干辐照对LiNbO3:Fe晶体中从自散焦到自聚焦的动态转换过程的影响和控制作用.无论是从前向还是从背向加入非相干辐照,都能加快自散焦、自聚焦过程以及从自散焦到自聚焦的转换过程,增大折射率的变化值.当非相干辐照以一定的时间间隔重复辐照在晶体上时,透射功率能迅速地上升和下降,具有明显的开关效应.这种在非相干辐照控制下折射率的迅速改变有望应用于全光学开关器件.
关键词:
非相干辐照
光伏效应
自散焦
自聚焦 相似文献
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基于无偏压光伏光折变晶体,理论研究了热电效应和光伏效应共同作用下的稳态空间孤子对.从非相干耦合波方程出发,推导了热电光伏孤子对的数值解;采用有限差分方法,数值模拟了各类孤子对的强度包络.结果表明:在自散焦光伏光折变晶体中,当正的热电场远大于光伏场时,亮-亮孤子对可以存在;当暗-暗或者灰-灰孤子对存在时,负的热电场可以增强自散焦效应,进而减小孤子的半峰全宽.各类孤子对的半峰全宽可以通过改变热电场的大小而加以操控.此外,非相干耦合热电光伏孤子对可以在一定条件下分别退化成热电孤子对或者光伏孤子对.借助晶体的热电效应,可以使光折变晶体LiNbO3从自散焦转变成自聚焦,从而灵活控制晶体中孤子对的特性. 相似文献
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基于超常介质中超短脉冲传输的非线性薛定谔方程,解析得到了两种精确的亮、暗类孤子解,并详细讨论了在超常介质中该亮、暗类孤子的存在条件和传输特性.结果发现,在自散焦超常介质的正、负折射区域,该类亮孤子可以存在于反常色散区,这与常规介质中亮孤子存在于自散焦介质中的正常色散区不同;而在自聚焦超常介质的反常色散区,该类暗孤子可以存在于正、负折射率区,在自散焦超常介质的反常色散区,该类暗孤子仅存在于负折射区间.此外,我们数值研究了该类亮、暗孤子的存在条件不能严格满足时的传输稳定性,结果显示,在一定的归一化频率区间,该类亮、暗孤子都能够较稳定地传输. 相似文献
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We present a theory for a new type of optical spatial soliton that is based on the angle hole burning mechanism of photoisomerization in some polymers. We predict that the photoisomerization nonlinearity can support steady-state dark and bright spatial solitons in the polymer. We also discuss the dependence of the FWHM of the spatial soliton on wavelengths of the background beams and on the ratio of the intensity of the background beam to that of the signal beam. 相似文献
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By using the extended hyperbolic function method,we have studied a quintic discrete nonlinear Schr(o)dinger equation and obtained new exact localized solutions,including the discrete bright soliton solution,dark soliton solution,bright and dark soliton solution,alternating phase bright soliton solution,alternating phase dark soliton solution,and alternating phase bright and dark soliton solution,if a special relation is bound on the coefficients of the equation. 相似文献
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We propose a new design of a security scheme by using the nonlinear behaviors of temporal dark and bright solitons within a micro-ring resonator system for signal security application. When a dark soliton pulse is input into the proposed system, the chaotic signal is generated, where the required bright soliton pulse can be retrieved and detected by the add/drop filtering device. The chaotic wave form can be cancelled by using an add/drop device, which can be connected and used in the communication link. By using the appropriate ring parameters, simulation results obtained have shown that the soliton conversion can be performed. The ring radii used are within the ranges from 5 to 10 μms and Aeff=0.10-0.50 μm2. In application, the chaotic signal is generated and formed by the dark soliton within a nonlinear micro-ring device. This can be seen by using the add/drop device, where the bright soliton is formed and detected, which is available to use in communication link. The different temporal soliton response time is seen, the response times of 169 and 84 ns are noted for temporal dark and bright solitons, respectively, which can also be used to form the security key. 相似文献
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一种基于非线性光纤环镜开关特性的超短光孤子产生方法 总被引:3,自引:3,他引:0
提出了一种利用非线性光纤环镜的开关特性将连续波同时转化为亮孤子和暗孤子的新方法 ,即让连续波和另一波长的调制脉冲串共同耦合入光纤环镜 ,交叉相位调制使得一部分连续波被环镜透射 ,其余部分被反射 ;再让透射波和反射波分别在反常色散光纤和正常色散光纤中传输 ,自相位调制和群速度色散之间的相互作用使得透射波和反射波分别演化为亮、暗孤子。数值计算表明 ,该方法不仅可产生脉宽比调制脉冲窄、重复频率比调制脉冲高的亮孤子和暗孤子 ,而且几乎可将全部的连续波能量转化为孤子能量。 相似文献
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本文从理论上研究了主克尔型介质中非束缚态空间亮孤子的传输行为。数值计算结果表明:在主克尔型χ(3)+χ(5)介质中可以传输非束缚态空间亮孤子。传输稳定性与其背景平面波的横向渐近传播常数q和χ(3),χ(5)系数有关,非平凡相位因子在三、五阶效应竞争中的平衡作用,是获得非束缚态空间亮孤子稳定传输的关键。 相似文献
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