共查询到16条相似文献,搜索用时 375 毫秒
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本文基于光波在宇称时间对称波导中传输的理论模型,数值研究各阶亮孤子在罗森莫尔斯势宇称时间对称波导中的传输特性。宇称时间对称波导的折射率分布对光具有线性聚焦作用,而增益/损耗分布可以引起光束能量的横向流动。研究结果表明:当折射率调制深度为正时,一阶亮孤子在该波导中传输形成波浪形光束。当折射率调制深度为负时,一阶亮孤子分裂形成两束光,一束光发生弥散,另一束光以一定的速度向前传输,而增益/损耗调制深度会影响分裂后光束的传输行为;二阶亮孤子在较低的增益/损耗调制深度下传输形成稳定的呼吸光束;三阶亮孤子在传输过程中出现光波周期分裂与会聚现象;四阶及其以上高阶亮孤子在该波导中都不能稳定传输。此研究结果可为宇称时间对称在光波导中的应用提供一定的理论依据。 相似文献
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应用等效粒子近似方法研究了光学空间孤子在带有局域和非局域非线性横向非均匀介质中的传输动力学行为.发现孤子在传播过程中横向的周期性振荡.折射率调制幅度和波导的归一化宽度决定了振荡周期的大小.介质的非局域对振荡振幅有着较小的影响.模拟了孤子传输过程,所得数值结果与理论分析符合很好.此外,模拟传输还发现多孤子束缚态能够在这个模型中稳定传播.这种振荡特性或许可以应用于光学路由器、转换器、开关等. 相似文献
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本文研究了矩形和圆形截面铅玻璃介质中强非局域空间光孤子的传输特性.基于镜像法,光束在铅玻璃中的传输被分成独立的两个过程,即孤子的形成和孤子的整体偏转.孤子的形成不依赖于边界,它来源于入射源光束本身形成的折射率分布的作用,所以形成孤子的临界功率只与材料的性质和入射光束束宽有关.孤子的整体偏转在本质上来源于边界的作用,其偏转力在数值上等同于所有镜像光束与源光束之间的作用力.截面圆形和截面矩形的边界分别"镜像"出一个和无穷多个镜像光束,进而导致不同边界条件下孤子不同的偏转轨迹.文中解析求得的孤子的临界功率以及两
关键词:
空间光孤子
强非局域
镜像法
铅玻璃 相似文献
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从标量Helmholtz方程出发,推导了对数饱和非线性介质中光场满足的非线性Schr dinger方程(NLSE)。通过与梯度折射率下的光场满足的方程比较,发现高斯光束在对数型饱和非线性介质中可自诱导梯度折射率。利用数值计算,详细地讨论了自诱导梯度折射率对高斯光束传输特性的影响。发现高斯光束在其自诱导的梯度折射率的影响下,呈振荡形式的准稳定的传输。光束注入介质中的初始状态,直接影响着光束的振荡形式(先发散还是先聚焦)、振荡深度(幅度)、振荡周期。得到高斯光束形成孤子的条件,以及若使高斯光束在对数饱和非线性介质中保持小损耗、高稳定的传输,应该使光束在阈值(孤子条件)附近注入介质的结论。 相似文献
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The propagation of spatial solitons is systematically investigated
in nonlocal nonlinear media with an imprinted transverse periodic
modulation of the refractive index. Based on the variational
principle and the infinitesimal approximation of Maclaurin series
expansion, we obtain an analytical solution of such nonlocal spatial
solitons and an interesting result that the critical power for such
solitons propagation is smaller than that in uniform nonlocal
self-focusing media. It is found that there exist thresholds in
modulation period and lattice depth for such solitons. A stable
spatial soliton propagation is maintained with proper adjustment of
the modulation period and the lattice depth. 相似文献
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讨论了光孤子传输中,由脉冲包络的相位变化产生的啁啾与孤子传输的关系。数值计算表明,当孤子脉冲收缩、展宽时,啁啾总是改变符号,利用啁啾也可以定出孤子传输的光纤临界长度(即孤子传输中集总放大器的间隔),其效果比用脉宽恢复定出的临界长度要好 相似文献
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光脉冲在标准单模光纤中演化形成孤子的实验研究 总被引:3,自引:0,他引:3
利用二次谐波频率分辨光学门脉冲分析仪从实验上分析研究了具有啁啾的10 GHz光脉冲在不同输入功率下演化形成孤子的规律和特点。实验发现:输入脉冲在光纤中传输3.5个色散长度时,其时间宽度、频率啁啾和时间带宽积都随着输入功率的增加而减小。当输入功率大于一阶孤子功率的理论值时,光脉冲能够演化形成孤子;脉冲在随后传输过程中其宽度基本保持不变,波形、频率啁啾和时间带宽积仍随着传输距离的变化而变化;输入功率越高,形成的一阶孤子脉冲的宽度越窄。当输入功率小于一阶孤子功率的理论值时,输出脉冲的时间宽度随着传输距离的增加而增加,频率啁啾随着传输距离的增加而减小,光脉冲不能演化形成孤子。 相似文献
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The properties of controllable soliton switching in Kerr-type optical lattices with different modulation are investigated theoretically and simulated numerically. The results show that the optical lattices can be available for all-optical soliton switching through utilization for length-scale competition effects. And through longitudinal exponential-asymptotic modulation for the linear refractive index, the properties of soliton switching in the optical lattices can be improved. The
number of output channels of soliton switching can be controlled by the
parameters such as incident angle, asymptotic rate of longitudinal
modulation, guiding parameter and form factor. 相似文献
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We address the phenomenon of self-splitting of N-soliton bound states into their individual soliton constituents in a planar Kerr medium with a waveguide that has a triangular linear refractive index. The splitting is due to the fact that each soliton component experiences different change of propagation angle which is driven by the potential introduced by the refractive index variation and the soliton amplitude. Our numerical simulations show that the break up only disturbs the propagation angle of each single soliton constituent but not its amplitude. 相似文献
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We present an analytical and numerical investigation of the propagation of spatial solitons in a nonlinear waveguide with ramp linear refractive index profile (ramp waveguide). For the propagation of a single soliton beam in a ramp waveguide, the particle theory shows that the soliton beam follows a parabolic curve in the region where the linear refractive index increases and a straight line outside the waveguide. The acceleration of the soliton depends on the beam intensity: higher amplitude solitons experience higher acceleration. Numerical calculations using an implicit Crank–Nicolson scheme confirm the result of the particle theory. Combining these propagation properties with the theory about bound-N-soliton, we study the break up of such a bound-N-soliton in a ramp waveguide. In a ramp waveguide, a bound-N-soliton will always be splitted into N independent solitons with the higher amplitude soliton emitted first. The amplitude of the separated solitons after break up are calculated using the soliton theory as if the solitons are independent. Numerical simulations show that the results agree quite well with this theoretical prediction, indicating that the interaction during break up has only little influence. 相似文献