Properties of Controllable Soliton Switching in Optical Lattices with Longitudinal Exponential-Asymptotic Modulation

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.     

Phase-induced switching in fiber nonlinear directional coupler

A numerical study of soliton switching characteristics and the maximum output coupling by the relative phase change of a control pulse is carried out for input powers, coupled coefficient and input soliton width. It is shown that input powers ratio, coupled coefficient and input soliton width play important roles in this mode of soliton switching and that these effects may lead to useful soliton switching if the relative phase of the control pulse is monitored judiciously.     

Dark soliton switching in an NLDC in the presence of higher-order perturbative effects

Dark soliton switching in a nonlinear directional coupler in the presence of intermodal dispersion, cross-phase modulation (CPM), third-order dispersion, Raman effect, and self-steepening effect is reported for the first time. It is shown that, with the exception of CPM, all of the other perturbative effects have almost no effect on the switching characteristics of the dark soliton switch, which is an improvement over the corresponding bright soliton switch. Although the CPM increases the critical power of dark soliton switching, the soliton pulse remains stable inside the coupler during its propagation.     

Soliton switching study using new normalized nonlinear Schrödinger equations

Soliton switching in a nonlinear directional coupler (NLDC) is studied by using new normalized nonlinear Schrödinger equations (NLSE). The resulted equations have one parameter κL_D only, this feature greatly simplifies the numerical study of soliton coupling in a NLDC, and it enables us to derive the soliton switching conditions based on numerical analysis. Numerical results show that most of the input soliton energy remains in the launched waveguide when input soliton normalized peak power is bigger than 2.5. It is contrary to the existing theoretical expectations which were derived using variational approach. The fundamental soliton switching conditions is also expressed in terms of input soliton pulse width. In addition, it is found that frequency chirp degrades soliton switching performance in a NLDC.     

Spatial soliton optical switches: a soliton-based equivalent particle approach

The spatial soliton plays a fundamental role as a robust, particle-like object which can be manipulated to switch or spatially scan collimated light channels or optical pulses which are incident at an oblique angle to an interface separating two or more selffocusing Kerr slab dielectrics. The underlying equivalent particle/multiparticle theory can also be employed to predict stability properties of nonlinear surface or guided waves, to derive an analytic expression for the nonlinear Goos-Hanchen shift at a nonlinear interface and to quantify the effect of material diffusion, linear and twophoton absorption on the switching behaviour of the light beam. Pulsed spatial switching effects are studied in order to illustrate the general predictive power of the equivalent particle theory.     

Compton散射下多信道平面光波导的空间光孤子开关

应用量子微扰理论和多光子非线性Compton散射模型,对Compton散射下多信道平面光波导的空间光孤子开关进行了研究.结果表明:在横向具有正弦形周期折射率调制的非线性平面光波导的多信道系统中,原先束缚在一个信道中的孤子可以靠由入射和散射光形成的耦合控制光点,通过交叉相位调制横向吸引孤子波束,使孤子从原信道切换到邻近信道,从而实现光孤子开关的功能.控制光点可由耦合光在势谷之间的横向聚焦来实现.散射既能使控制光点的有效强度的阈值和孤子的辐射损耗增大,势垒增高,幅度下降较小,有利于孤子开关的形成;又能使波束展宽较宽,并存在开关被破坏的危险.由此可见,Compton散射下恰当控制入射激光强度是实现孤子开关的关键.     

Dynamics of bound vector solitons induced by stochastic perturbations: Soliton breakup and soliton switching

We respectively investigate breakup and switching of the Manakov-typed bound vector solitons (BVSs) induced by two types of stochastic perturbations: the homogenous and nonhomogenous. Symmetry-recovering is discovered for the asymmetrical homogenous case, while soliton switching is found to relate with the perturbation amplitude and soliton coherence. Simulations show that soliton switching in the circularly-polarized light system is much weaker than that in the Manakov and linearly-polarized systems. In addition, the homogenous perturbations can enhance the soliton switching in both of the Manakov and non-integrable (linearly- and circularly-polarized) systems. Our results might be helpful in interpreting dynamics of the BVSs with stochastic noises in nonlinear optics or with stochastic quantum fluctuations in Bose–Einstein condensates.     

Influence of Randomly Varying Birefringence on Soliton Switching

In this paper, the effects of the randomly varying birefringence on soliton switching in the twin-core fiber are discussed through a nonlinear coupling equation , some novel and useful results on soliton switching are obtained.     

Effect of Varying Dzyaloshinskii-Moriya Interaction on the Bistable Nano-Scale Soliton Switching

The effect of Dzyaloshinskii-Moriya (D-M) interaction on the bistable nano-scale soliton switching offers the possiblity of developing a new innovative approach for data storage technology. The dynamics of Heisenberg ferromagnetic spin system is expressed in terms of generalized inhomogeneous higher order nonlinear Schrödinger (NLS) equation. The bistable soliton switching in the ferromagnetic medium is established by solving the associated coupled evolution equations for amplitude and velocity of the soliton using the fourth order Runge-Kutta method numerically.     

A variational analysis of soliton switching in an NLDC with saturating non-linearity

A comparative analysis of soliton switching in a non-linear directional coupler with saturating non-linearity is carried out by a variational method. Two models of fractional non-linearity, one the usual unaveraged and the other obtained after averaging over the fibre cross-section, are considered. It is shown that the switching characteristics differ (for the same set of fibre parameters), qualitatively as well as quantitatively, for these models. The soliton switching characteristics in both the models are obtained, compared and discussed.     

Vector soliton switching in a fiber nonlinear directional coupler

This paper reports a detailed numerical study of soliton switching in a high as well as low birefringent nonlinear coupler. It is shown that by controlling the polarization angle one can have nearly 100% transmission with excellent switching characteristics. It is shown that soliton remains stable during its propagation inside the coupler. However it is observed that high birefringent coupler exhibits relatively better soliton stability. We show that the coupler could be used as a soliton switch even at an input peak power less than the critical power, the power at which 50-50 power sharing takes place between the two cores, just by a judicious choice of the polarization angle.     

非线性光纤耦合器孤子传输的相敏能量交换特性

从动力学的角度出发,分析了非线性双芯光纤耦器中不同芯层内孤子脉冲的相位对能量交换特性的影响,只要初始注入孤子信号的相位差选择恰当。     

Steering of weak-light spatial solitons in a resonant lambda-type atomic system

We study steering of weak-light solitons in a resonant lambda-type atomic system. Signal soliton steering can be realized via input angle and power control of the control soliton. It is shown that, the deflection angle of a vertical input signal soliton increases linearly with the increase of the input angle of the control soliton due to the repulsive effect in collision, and thus leads to the increase of the output position shift of the signal soliton. When a signal soliton is input parallel with a control soliton, the output position shift of the signal soliton depends parabolically on the normalized power of the control soliton. Decreasing their soliton separation can increase the output position shift of the signal soliton. These properties may be useful in all-optical soliton switching and optical information processing, etc.     

全光双准稳态空间孤子

观察到一种双准稳态光折变空间孤子.这种孤子是(1+1)维的.它的形成不需要外加电场,是全光的.孤子的形成过程具有全光开关效应 关键词： 光折变空间孤子 双准稳态 全光开关     

Spatial switching of quadratic solitons in engineered quasi-phase-matched structures

We show that a variety of quasi-phase-matched structures with engineered patterns can potentially be used for soliton control in quadratic nonlinear media. We study geometries with dislocations, tilts, and wells and predict spatial switching between different output soliton states. Experimental implementation conditions are discussed.     

Nonlinear beam interactions in semi-infinite waveguide arrays

The interactions between coherent beams launched near the interface of one-dimensional semi-infinite Kerr-type nonlinear waveguide arrays have been theoretically investigated. We have explored the effect of the input intensities, the relative phase of the optical beams, and the modulation of the refractive index of the optical lattices on nonlinear beam interaction dynamics. For in-phase beams with different incident intensities, the highly-localized spatial soliton was dragged in a discrete fashion by a low-intensity diffracting beam. Anomalous fusion of two out-of-phase beams, and energy exchange between the excited channels were observed at high intensities. The possibility of employing nonlinear interactions for optical signal re-addressing, all-optical switching is also discussed.     

Scattering and spiraling of solitons in a bulk quadratic medium

We analyze the interactions of (2+1) -dimensional parametric solitons and demonstrate nonplanar beam switching in a bulk X((2)) medium, which includes controllable soliton repulsion, spiraling, and fusion. An analytical model predicting the results of the soliton scattering is derived and verified by direct numerics.     

A comparative numerical study of soliton switching in a nonlinear directional coupler with saturating nonlinearity

A detailed numerical study of soliton switching in a nonlinear directional coupler with saturating nonlinearity is carried out. All commonly used models have been studied. Relevant physical characteristics for switching have been determined, compared and discussed.     

All optical quasi-steady-state photorefractive spatial solitons

We have created a one- (rather than two-) dimensional quasi-steady-state photorefractive spatial soliton induced by a laser beam instead of an applied electric field. The formation of this type of spatial soliton depends on the intensity of the self-trapped beam, which is different from quasi-steady-state spatial solitons reported in the literature. The optically induced spatial soliton can be exploited in all optical switching applications.     

Comparison of different switching techniques in a cavity soliton laser

We compare three different switching techniques for the control of cavity solitons in a VCSEL-based cavity soliton laser, one incoherent and the other two semicoherent with different injection frequencies. We show that the switching dynamics and energies can be very different depending on the type of injection.