共查询到20条相似文献,搜索用时 109 毫秒
1.
Parametric amplification of soliton steering in optical lattices 总被引:1,自引:0,他引:1
We report on the effect of parametric amplification of spatial soliton swinging in Kerr-type nonlinear media with longitudinal and transverse periodic modulation of the linear refractive index. The parameter areas are found where the soliton center motion is analogous to the motion of a parametrically driven pendulum. This effect has potential applications for controllable soliton steering. 相似文献
2.
3.
We investigate the soliton steering in weakly nonlocal nonlinear media with harmonic modulation of the refractive index. It is shown that the weak nonlocality originated from the nonlocal nonlinear response of medium induces a transverse modulation of the refractive index, which leads to the occurrence of interplay between the weak nonlocality-induced transverse modulation and the harmonic modulation. Thus, one can control the soliton steering in weakly nonlocal medium, such as nematic liquid crystal, by employing the competition between the weak nonlocality parameter and the lattice depth. 相似文献
4.
Yingji He Xing Zhu Dumitru Mihalache Jinglin Liu Zhanxu Chen 《Optics Communications》2012,285(15):3320-3324
We study the existence and stability of solitons forming in PT–symmetric optical lattices with spatially periodic modulation of the local strength of the nonlinear media. We found that the spatial modulation of the nonlinearity significantly affects the stability of solitons in PT–symmetric optical lattices. With the decrease of the strength of nonlinear refractive index modulation, the soliton's stability domain increases, whereas with the increase of the period of nonlinear refractive index modulation, the corresponding soliton's stability range narrows. In addition, we also investigate the influence of variation of the amplitude of the linear PT–symmetric lattice potential on soliton dynamics, in the presence of spatially periodic modulation of nonlinearity. 相似文献
5.
利用解析和数值方法研究了在具有横向折射率周期性调制的克尔型非线性介质中光学格子孤子的传输,得到了孤子参数的演化方程以及格子孤子的形成和稳定传输的条件.结果表明:当光束的入射角小于某临界角度时,光束可被类似波导形式的路径俘获而稳定传输,该临界角随折射率调制周期、调制深度的增加而增大,且光束越窄临界值越大.此外,线性空间啁啾虽然对光束传输的中心位置没有任何影响,但会导致光束发散从而破坏格子孤子的形成和稳定传输,对此提出了采用特定功率取值来补偿啁啾作用从而形成格子孤子的方案.
关键词:
光孤子
光学格子
光传输
矩方法 相似文献
6.
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
7.
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
8.
We address the existence and properties of solitons in thermal media with periodic modulation of linear refractive index. Many kinds of solitons in such optical lattices, including symmetric and antisymmetric lattices, are found under different conditions. We study the influence of the refractive index difference between two different layers on solitons. It is also found that there do not exist cutoff value of propagation constant and soliton power for shifted lattice solitons. In addition, the solitons launched away from their stationary position may propagate without oscillation when the confinement from lattices is strong. 相似文献
9.
Soliton modes, stability, and drift in optical lattices with spatially modulated nonlinearity 总被引:1,自引:0,他引:1
We put forward new properties of lattice solitons in materials and geometries where both the linear refractive index and the nonlinearity are spatially modulated. We show that the interplay between linear and out-of-phase nonlinear refractive index modulations results in new soliton properties, including modifications of the soliton stability and transverse mobility, as well as shape transformations that may be controlled, e.g., by varying the light intensity. 相似文献
10.
Holographic solitons 总被引:5,自引:0,他引:5
We propose a new kind of an optical spatial soliton: the holographic soliton. This soliton consists of two mutually coherent field components that interfere, induce a periodic change in the refractive index, and simultaneously are Bragg diffracted from the grating. Holographic solitons are formed when the broadening tendency of diffraction is balanced by phase modulation that is due to Bragg diffraction from the induced grating. Holographic solitons are solely supported by cross-phase modulation arising from the induced grating, not involving self-phase modulation at all. 相似文献
11.
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
12.
We investigate numerically surface-wave solitons occurring at the interface between semi-infinite linear and thermal nonlinear optical media, with the refractive index of the linear medium being greater than that of the nonlinear medium (in the absence of light). We find that the threshold energy flows of the existence of the surface solitons depend on the linear refractive index difference of the two media. Their fitting empirical formula has been obtained. Furthermore, we elucidate that the optical beams propagating in thermal nonlinear optical media, either as a single surface soliton or as a dipole surface soliton, can be attracted to the surface, even when launched from far away. 相似文献
13.
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
14.
K. A. Brzdąkiewicz U. A. Laudyn M. A. Karpierz T. R. Woliński J. Wójcik 《Opto-Electronics Review》2006,14(4):287-292
We investigate linear and nonlinear light propagation in the photonic crystal fibers infiltrated with nematic liquid crystals.
Such a photonic structure, with periodic modulation of refractive index, which could be additionally controlled by the temperature
and by the optical power, allows for the study of discrete optical phenomena. Our theoretical investigations, carried out
with the near infrared wavelength of 830 nm, for both focusing and defocusing Kerr-type nonlinearity, show the possibility
of the transverse light localization, which can result in the discrete soliton generation. In addition, we present the preliminary
experimental results on the linear light propagation in the photonic crystal fiber with the glycerin-water solution and 6CHBT
nematics, as the guest materials. 相似文献
15.
Inhibition of light tunneling in chirped and longitudinally modulated semi-infinite waveguide arrays
The inhibition of light tunneling in chirped and longitudinally modulated semi-infinite waveguide arrays where the refractive index is linearly modulated in the transverse direction and harmonically modulated along the light propagation direction is considered. We report on the effect of the refractive index transverse amplitude modulation rate, longitudinal modulation frequency and depth on tunneling inhibition in both linear and nonlinear regimes. We show that in the linear regime an optimal value for the transverse amplitude modulation rate of refractive index exists and can determine the optimal longitudinal modulation frequency or depth leading to a maximum of distance-averaged power fraction. In the nonlinear regime the tunneling inhibition dynamics is affected dramatically by the transverse amplitude modulation rate and the associated electric field amplitude of the input beam. 相似文献
16.
We report experimental evidence of soliton reflection at the boundary of quadratic nonlinear media. The evolution of beams incident upon the interface of periodically poled LiNbO3 and uniform LiNbO3 is considered; in the whole device the linear refractive index is homogeneous. Linear beam transmission and soliton reflection at the nonlinear phase-mismatched boundary were observed. Numerical simulations that correspond to the experiments are also presented. 相似文献
17.
Properties of conservative and dissipative Bragg solitons formed in single-mode optical fibers with induced longitudinal modulation of the refractive index are analyzed beyond the standard approximation of coupled modes, or of slowly varying amplitudes. It is shown that, if the initial velocity of a Bragg soliton is smaller than a critical value, the soliton stops in the process of propagation. 相似文献
18.
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
19.
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 intoN 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.
On Leave from Jurusan Matematika, Universitas Brawijaya, Jl. MT Haryono 167 Malang Indonesia. 相似文献
20.
We elucidate the existence, stability and propagation
dynamics of multi-spot soliton packets in focusing saturable media.
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 homogeneous 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 additional
freedom to control the shape of solitons by adjusting the modulation
depths beside the interface. 相似文献