Dispersion-managed soliton in a strong dispersion map limit

A dispersion-managed optical system with stepwise periodic variation of dispersion is studied in a strong dispersion map limit in the framework of the path-averaged Gabitov-Turitsyn equation. The soliton solution is obtained by analytical and numerical iteration of the path-averaged equation. An efficient numerical algorithm for finding a DM soliton shape is developed. The envelope of soliton oscillating tails is found to decay exponentially in time, and the oscillations are described by a quadratic law.     

Dispersion-managed soliton in optical fibers with zero average dispersion

A dispersion-managed optical system with stepwise periodic variation of dispersion is studied in the framework of a path-averaged Gabitov-Turitsyn equation. The soliton solution is obtained by means of iterating the path-averaged equation. The dependence of soliton parameters on dispersion map strength is investigated, together with the oscillating tails of the soliton.     

Dispersion-managed soliton dynamics

We obtain and solve algebraic eigenvalue equations that predict the dependence of the pulse energy of a dispersion-managed soliton on pulse duration, chirp, and dispersion-map parameters. We demonstrate that a variational ansatz based on a Gaussian pulse shape remains useful even when the actual pulse shape is not Gaussian, and we show that the enhancement factor saturates as the pulse duration decreases.     

Dispersion-managed soliton interactions in optical fibers

We simulated dispersion-managed soliton propagation and interaction in optical fibers. The energy-enhancement factor, together with the time-bandwidth product and the stretching factor, were calculated as a function of the difference in absolute values of accumulated dispersion in the fiber spans. The interaction strength of the dispersion-managed solitons was found to depend on the stretching factor. When this factor is less than 1.5, the interaction is weaker than for ideal solitons. When it is more than 1.5, there is a strong interaction between the pulses, which constrains the energy enhancement for practical applications.     

Optimal dispersion maps for wavelength-division-multiplexed soliton transmission

We propose an advantageous dispersion-management scheme for wavelength-division-multiplexed soliton transmission in which optimal launch points are obtained whose locations are independent of the fibers' dispersion parameters. Inasmuch as using such optimal launch points minimizes dispersively shed radiation, it is possible to optimize the transmission simultaneously in several different channels. For the particular case of a two-step dispersion map we demonstrate that this result can be achieved by proper choice of the fiber lengths.     

Dispersion-managed breathers with average normal dispersion

Analytic and numerical evidence is presented that demonstrates that a dispersion-managed breather can be supported in an optical fiber even when the average dispersion is in the normal regime. This nonlinear behavior, which is contrary to guiding-center theory, is shown to originate from the reversible dynamics associated with the strong quadratic chirp that is generated in both the anomalous and the normal dispersion regimes.     

Dispersion-managed solitons with net positive dispersion

Propagation of dispersion-managed solitons in the net positive-dispersion regime is studied. A new form of sideband generation that is due to perturbations is identified. Some collision anomalies are pointed out.     

Dispersion-managed solitons at normal average dispersion

We find that in a dispersion-managed fiber, in which the strength of the dispersion management is above some threshold, solitons can exist with normal average dispersion. When the normal average dispersion is below some limiting value there exist two soliton solutions with the same pulse duration and different pulse energies. When the normal average dispersion is above this limiting value, no soliton exists. Both higher-energy and lower-energy solitons are dynamically stable in the parameter range that we considered.     

Theory of guiding-center breathing soliton propagation in optical communication systems with strong dispersion management

We present a theory of chirped breathing pulse propagation in optical transmission systems with strong dispersion management. Fast changes of pulse width and chirp over one period are given by a simple model that is verified by direct numerical simulations. An average pulse evolution in the leading order is described by the nonlinear Schr?dinger equation, with additional parabolic potential that can be a trapping (when a grating is used) or a nontrapping (without a grating) type.     

Collisions in dispersion-managed soliton propagation

We study collisions in dispersion-managed soliton propagation for wavelength-division multiplexing application at zero net dispersion when the Gordon-Haus timing jitter is removed. We show that the collisions can lead to group-velocity changes and spectral collapse. Large channel separation ameliorates the effects. Filters prevent spectral collapse but do not affect the velocity changes.     

Dispersion-managed solitons in optical amplifier transmission systems with zero average dispersion

Soliton propagation in a cascaded dispersion-managed optical amplifier system with zero net dispersion is examined. We present a qualitative physical explanation for the recently discovered fact that a soliton with finite energy can propagate down a fiber line with zero or normal average dispersion. We describe a specific practical system for the main properties of such a soliton, namely, the dependence of the soliton power on the pulse width at chirp-free points and the soliton average energy and width at chirp-free points as functions of the dispersion-allocation (strength of the map) parameter.     

On the dispersion managed soliton

We review various methods used to study the dispersion managed soliton for nonlinear return-to-zero pulse propagation in optical fibers. A numerical averaging method, the guiding center soliton, the variational method both with a simple and with an extended ansatz, as well as the multiscale theory are discussed and numerically compared, allowing us to show their domains of applicability. Their relative merits and demerits are then exposed. (c) 2000 American Institute of Physics.     

Filter control polarization mode dispersion in dispersion managed soliton systems

In this paper, the dispersion managed soliton (DMS) transmission equation is built on considering the effects of polarization mode dispersion (PMD) and filter control. The DMS transmission of filtering control in constant birefringence fibers is firstly analyzed by varitional method, from which the evolving rules of characteristical DMS parameters are obtained. Secondly, the stability of DMS transmission and its timing jitter are investigated in the random varying birefringence fibers with the conventional model of PMD. The results reveal that filter control DMS system has powerful robustness to PMD effects and DMS's timing jitter can be decreased considerably with the help of filters.     

Diffraction effects on soliton propagation

An averaged-Lagrangian method is used to analyze diffraction effects on propagation of solitons of various types in homogeneous media. It is shown that diffraction can counteract the self-focusing of dark and gray envelope solitons described by the nonlinear Schrödinger equation and solitons described by the Korteweg-de Vries equation when the soliton intensities do not exceed certain values. Conversely, diffraction enhances the self-focusing of dark and gray envelope solitons described by the modified Korteweg-de Vries equation, kinks described by the sine-Gordon equation, and domain walls in the u 4 model, which is explained by mutual correlation between transverse and longitudinal soliton dynamics. Critical parameters that determine soliton stability with respect to self-focusing are found for several models.     

High-order soliton generation in dispersion flattened fiber

By using the amplified 10-GHz, 5.5-ps sech2 pulses with high quality and chirp-free from regeneratively mode-locked fiber laser (RMLFL) as the soliton source, 2-5 order optical soliton phenomena are observed successfully in a 4.28-km dispersion flattened fiber. The experimental results agree well with the theoretical calculation.     

亚皮秒啁啾孤子在凸形色散与线性色散平坦光纤中的传输特性比较

提出采用凸形色散平坦光纤(DFF-CVDP)传输亚皮秒啁啾孤子,利用分步傅里叶方法数值研究了亚皮秒啁啾孤子在DFF-CVDP中的传输特性,并与在线性色散平坦光纤(DFF-LDP)中的传输特性做了比较。结果表明,孤子脉冲在上述两种光纤中传输时,光纤损耗导致了孤子脉冲宽度随传输距离增加稍有展宽,脉冲方均根谱宽随传输距离增加逐渐减小。在DFF-LDP中,脉冲展宽更快,正啁啾对脉冲展宽的影响比负啁啾的影响更大,正啁啾对应的方均根光谱比其他情况下的宽得多。啁啾脉冲时域宽度随传输距离增加出现了衰减振荡,振荡周期和振幅随啁啾参量|C|的增加而增大。光孤子脉冲在两种光纤中传输时域波形保持不变,仍具有孤子特性。在DFF-LDP中,3β使得脉冲光谱红移从而诱导了脉冲时延,负啁啾减弱了3β的作用,正啁啾加强了β3的影响。在DFF-CVDP中传输可以忽略3β的影响。     

Free electron lasers and soliton propagation

Non linearities, due to the intensity growth, govern the saturation mechanisms in free electron laser devices. A toy model to describe the dynamical behavior of the device from small signal regime to saturation is obtained from the Ginzburg–Landau equation. It is shown that a proper extension of the model suggests the existence of solitary optical pulses.