Families Of Spatial Solitons Research Articles

线性和二次电光效应共同主导的非相干耦合空间孤子族

线性和二次电光效应共同主导的非相干耦合空间孤子族

Higher-order solitons in amplitude-disordered waveguide arrays

We investigate the existence and stability of different families of spatial solitons in optical waveguide arrays whose amplitudes obey a disordered distribution. The competition between focusing nonlinearity and linearly disordered refractive index modulation results in the formation of spatial localized nonlinear states. Solitons originating from Anderson modes with few nodes are robust during propagation. While multi-peaked solitons with in-phase neighboring components are completely unstable, multipole-mode solitons whose neighboring components are out-of-phase can propagate stably in wide parameter regions provided that their power exceeds a critical value. Our findings, thus, provide the first example of stable higher-order nonlinear states in disordered systems.

Incoherently coupled spatial soliton families in biased two-photon photorefractive crystals with both the linear and quadratic electro-optic effect

Different from the cases discussed preciously, nonlinear changes of refractive index in the photorefractive materials are influenced by both the linear and quadratic electro-optic effect simultaneously now. Here we present the evolution equations of one-dimension incoherently coupled spatial soliton families due to two-photon effect in biased photorefractive crystals with both the linear and quadratic electro-optic effect and discuss their existence conditions and properties in detail. Our analysis indicates that these soliton families can exist in all three possible realizations: dark-dark, bright-bright and dark-bright provided that the incident beams have the same polarization, wavelength and are mutually incoherent. Finally, the stabilities of these soliton families have been discussed by means of beam propagation methods.

Universal theory of incoherently coupled spatial solitons families in photorefractive crystals

The incoherently coupled soliton families are predicted in photovoltaic photorefractive crystals illuminated by E-polarized incoherent uniform back-ground irradiation with a divider resistance under steady-state conditions. These soliton families can be established provided that the incident optical beams share the same polarization and wavelength, and are mutually incoherent. When these incoherent coupled soliton families propagate together, all components can propagate stably in photorefractive crystal. Moreover, such soliton families reduce into spatial soliton or incoherently coupled soliton pairs when they contain only one or two components. The 14 kinds of incoherently coupled spatial soliton families can be obtained from this theory by adjusting the value of the divider resistance, E-polarized back-ground irradiation, the biased electric field and photovoltaic electric field. Previous theories advanced individually elsewhere for these soliton families can be obtained by simplifying this theory under appropriate conditions.

Screening-photovoltaic grey spatial soliton families in biased two-photon photovoltaic photorefractive crystal

To study the grey spatial soliton families in biased two-photon photovoltaic photorefractive crystal, the dynamical evolution equation and the numerical solution of the grey spatial soliton families were established. The numerical results show that the incoherently coupled screening-photovoltaic grey soliton families can be established provided the multiple incident beams have the same polarization, wavelength, and are mutually incoherent. The screening-photovoltaic grey soliton families can be considered as the united form of screening grey soliton families and open- or closed-circuit photovoltaic grey soliton families due to two-photon photorefractive effect.

Incoherently coupled spatial soliton families in photorefractive polymers

It is shown theoretically that incoherently coupled bright or dark spatial soliton families can be realized in biased guest–host photorefractive polymers under steady-state conditions. These soliton families can be established provided the multiple carrier beams share the same polarization, wavelength, and are mutually incoherent. These soliton families will reduce to soliton pairs when they contain only two components. Moreover, the stability of such soliton families has been discussed by the numerical method.

Incoherently coupled spatial soliton families in centrosymmetric two-photon photorefractivecrystals

It is shown theoretically that incoherently coupled dark, bright and bright–dark hybridsoliton families can exist in centrosymmetric two-photon photorefractive crystals understeady-state conditions. These soliton families can be established provided that theincident optical beams share the same polarization and frequency, and are mutuallyincoherent.

Families of spatial solitons in a two-channel waveguide with the cubic-quintic nonlinearity

We present eight types of spatial optical solitons which are possible in a model of a planar waveguide that includes a dual-channel trapping structure and competing (cubic-quintic) nonlinearity. The families of trapped beams include “broad” and “narrow” symmetric and antisymmetric solitons, composite states, built as combinations of broad and narrow beams with identical or opposite signs (“unipolar” and “bipolar” states, respectively), and “single-sided” broad and narrow beams trapped, essentially, in a single channel. The stability of the families is investigated via the computation of eigenvalues of small perturbations, and is verified in direct simulations. Three species–narrow symmetric, broad antisymmetric, and unipolar composite states–are unstable to perturbations with real eigenvalues, while the other five families are stable. The unstable states do not decay, but, instead, spontaneously transform themselves into persistent breathers, which, in some cases, demonstrate dynamical symmetry breaking and chaotic internal oscillations. A noteworthy feature is a stability exchange between the broad and narrow antisymmetric states: in the limit when the two channels merge into one, the former species becomes stable, while the latter one loses its stability. Different branches of the stationary states are linked by four bifurcations, which take different forms in the model with the strong and weak coupling between the channels.

Incoherently Coupled Grey Photovoltaic Spatial SolitonFamilies

A theory is developed for incoherently coupled grey photovoltaic solitonfamilies in unbiased photovoltaic crystals. Both the properties and theforming conditions of these soliton families are discussed in detail.The theory can also be used to investigate the dark photovoltaic solitonfamilies. Some relevant examples are presented, in which thephotovoltaic-photorefractive crystal is of lithium niobate type.

One-dimensional spatial soliton families in optimally engineered quasi-phase-matched lithium niobate waveguides.

The advantage for quadratic soliton generation of engineering the quasi-phase-matching period near the input of lithium niobate slab waveguides is demonstrated. This approach allows members of one-dimensional quadratic soliton families with different values of the wave-vector mismatch to be cleanly excited and to be characterized by quantitative intensity-profile measurements of both the fundamental and the second-harmonic soliton components.