Two-dimensional laser soliton complexes with weak, strong, and mixed coupling

A review is given of features and motion of two-dimensional dissipative solitons in lasers and laser amplifiers with saturable absorption. We present a rich variety of stable complexes with weak, strong, and mixed coupling of individual laser solitons. The type of coupling is determined by the topology of the distribution of energy flows within the complex. We reveal the existence of stable dissipative soliton complexes with curvilinear motion of their centre of mass. This type of motion results from the field distribution asymmetry and is well pronounced for complexes of laser solitons with strong and mixed types of coupling. Similar complexes are expected to exist in different spatially distributed nonlinear dissipative systems, including schemes with discrete dissipative solitons. PACS 42.65.Tg     

Curvilinear motion of multivortex laser-soliton complexes with strong and weak coupling

We reveal the existence of stable dissipative soliton complexes with curvilinear motion of their center of mass. This type of motion results from the field distribution asymmetry and is well pronounced for asymmetric complexes of laser solitons with strong coupling. We present results of numerical simulations of such complexes in a model of wide-aperture lasers or laser amplifiers with saturable gain and absorption. The complex consists of a pair of strongly coupled vortex solitons weakly coupled with a number of other vortex solitons. Similar complexes are expected to exist in different spatially distributed nonlinear dissipative systems, including schemes with discrete dissipative solitons.     

Regular and stochastic motion of dissipative optical solitons

Investigations of the motion of dissipative optical solitons and their complexes in wide-aperture nonlinearly optical (with coherent pump radiation) and laser (with incoherent pump radiation) systems have been reviewed. An important characteristic of dissipative solitons is the topology of the energy fluxes, which determines the internal structure of individual solitons and makes it possible to certainly separate the cases of the weak and strong interactions between the solitons. It has been shown that the character of the regular motion of dissipative soliton structures in a homogeneous system is determined by the symmetry of the transverse distributions of the intensity and energy flux; the motion of asymmetric structures is curvilinear. This is also valid for complexes of three-dimensional dissipative optical solitons, “laser bullets.” The extreme possibilities of localization of solitons are determined by quantum noises. The corresponding Brownian motion of the center of the dissipative optical soliton is characterized by a much lower level of the statistic dispersion of the coordinates of its center and velocity than that in the case of conservative solitons.     

全正色散多波长被动锁模耗散孤子掺镱光纤激光器

报道了一种带有周期性双折射光纤滤波器的全正色散多波长被动锁模耗散孤子掺镱光纤激光器. 通过数值模拟发现加入滤波器后激光器能输出多波长耗散孤子脉冲, 调节滤波器带宽大小可以得到不同波长个数和波长间隔的多波长锁模耗散孤子脉冲. 在激光器产生的四波长和五波长耗散孤子脉冲中观察到了耗散孤子分子, 并且通过调节滤波器参数和饱和功率可以改变多波长脉冲中耗散孤子分子的个数和波长. 这是在被动锁模光纤激光器中首次实现包含有耗散孤子分子的多波长脉冲. 另外还在实验上实现了全正色散双波长被动锁模耗散孤子的产生. 关键词： 全正色散 耗散孤子 多波长脉冲 孤子分子     

Collisions of one-dimensional asymmetric spatial laser solitons

Numerical simulation is used to find different scenarios of collisions between transverse 1D spatial moving asymmetric dissipative solitons and motionless symmetric dissipative solitons in a wide-aperture laser with a fast (inertialess) saturable absorber.     

Dual-wavelength dissipative soliton operation of an erbium-doped fibre laser using a nonlinear polarization rotation technique

We report on the generation of dual-wavelength dissipative solitons in a passively mode-locked fibre laser with a net normal dispersion using the nonlinear polarization rotation (NPR) technique. Taking the intrinsic advantage of the intracavity birefringence-induced spectral filtering effect in the NPR-based ring laser cavity, the dual-wavelength dissipative solitons are obtained. In addition, the wavelength separation and the lasing location of the dual-wavelength solitons can be flexibly tuned by changing the orientation of the polarization controller.     

Clusters of three-dimensional laser solitons and their collisions

A new class of clusters of three-dimensional dissipative inphase-and antiphase-coupled solitons is numerically found in a laser system with a saturable absorber. The orientation of clusters and their motion depend on the symmetry of spatiotemporal characteristic of the system and on the symmetry of arrangement of solitons in the cluster. An example of a nonplanar (spiral-like) trajectory of the center of a seven-soliton cluster possessing no symmetry elements is demonstrated. Collisions of moving soliton clusters, including those accompanied by exchange of solitons between clusters, are studied. Experimentally, three-dimensional dissipative optical solitons can be realized in a laser amplifier with a saturable absorber or in an extended resonator filled with a medium with nonlinear gain and absorption.     

Dissipative solitons of the Bose-Einstein condensate of excitons

A mirrorless scheme for forming dissipative solitons has been proposed. It consists of a thin layer of a nonlinear medium excited by coherent laser radiation. The existence of dark dissipative solitons of the Bose-Einstein condensate of excitons in such a semiconductor film has been numerically demonstrated. The sizes of an excition soliton and required laser-radiation level are two orders of magnitude smaller than the respective quantities for the case of optical dissipative solitons.     

基于高能量耗散型脉冲掺铒光纤激光器的实验研究

在正色散掺铒光纤激光器中,利用非线性偏振旋转技术实现自启动锁模,得到了具有极大光谱宽度的高能量、无波分裂耗散型脉冲.该耗散型脉冲的形成是腔内增益、损耗、非线性偏振旋转、正色散和其他非线性效应等共同作用的结果,其形成机理与传统的负色散激光器完全不同.当抽运功率为500mW时,该类型脉冲的光谱覆盖了1530—1660nm范围,半高全宽光谱宽度可达42nm以上.脉冲具有极大的正啁啾,其时间带宽积为483,而单脉冲总能量最大可达34.4nJ.     

Roadmap to ultra-short record high-energy pulses out of laser oscillators

Highly-chirped dissipative solitons of the cubic-quintic Ginzburg-Landau equation found in this work may provide a roadmap to design passively mode-locked laser oscillators that generate pulses of extremely high energy. We provide a region in the space of the system parameters where high-energy dissipative solitons are found, along with their typical spectral and temporal features.     

Structure of Energy Fluxes in Topological Three-Dimensional Dissipative Solitons

The internal structure of dissipative topological solitons has been revealed by example of three-dimensional dissipative optical solitons with one open and one closed dislocation lines of a wavefront. This structure is manifested in the existence of critical points, lines, and surfaces in the field of electromagnetic energy fluxes (Poynting vector). The conservation of the topological characteristics of such solitons, which can be formed in a homogeneous laser medium with saturated amplification and absorption or in lasers with quite large longitudinal and transverse dimensions, provides additional capabilities for information applications.     

Dissipative plasmon‐solitons in multilayer graphene

Nonlinear properties of a multi‐layer stack of graphene sheets are studied. It is predicted that such a structure may support dissipative plasmon‐solitons generated and supported by an external laser radiation. Novel nonlinear equations describing spatial dynamics of the nonlinear plasmons driven by a plane wave in the Otto configuration are derived and the existence of single and multi‐hump dissipative solitons in the graphene structure is predicted.     

High-energy dissipative soliton with MHz repetition rate from an all-fiber passively mode-locked laser

We experimentally demonstrate pulse energy enhancement in an all-fiber passively mode-locked laser operating in the large normal dispersion regime. By increasing the laser cavity length as well as its net cavity dispersion, the proposed laser, which is mode-locked by nonlinear polarization rotation, generates highly chirped dissipative solitons with pulse energies up to 9.4 nJ. The fundamental repetition rate is 2.3 MHz, and the pulse duration is 35 ps. Such low repetition rate as well as wide pulse width makes this mode-locked all-fiber laser a suitable oscillator to directly seed a fiber amplifier, which can be used as compact sources for high-power applications.     

Exploding dissipative solitons in the cubic-quintic complex Ginzburg-Landau equation in one and two spatial dimensions

We review the work on exploding dissipative solitons in one and two spatial dimensions. Features covered include: the transition from modulated to exploding dissipative solitons, the analogue of the Ruelle-Takens scenario for dissipative solitons, inducing exploding dissipative solitons by noise, two classes of exploding dissipative solitons in two spatial dimensions, diffusing asymmetric exploding dissipative solitons as a model for a two-dimensional extended chaotic system. As a perspective we outline the interaction of exploding dissipative solitons with quasi one-dimensional dissipative solitons, breathing quasi one-dimensional solutions and their possible connection with experimental results on convection, and the occurence of exploding dissipative solitons in reaction-diffusion systems. It is a great pleasure to dedicate this work to our long-time friend Hans (Prof. Dr. Hans Jürgen Herrmann) on the occasion of his 60th birthday.     

Conditions for the existence of laser bullets

Conditions for the existence of completely localized three-dimensional dissipative laser solitons—“laser bullets” in a medium with nonlinear amplification and absorption and frequency dispersion are studied. Solitons with different profiles are considered and the regions of their stable existence are found. The stability of spherical solitons is studied as a function of frequency mismatch of amplification and absorption lines by the method of direct numerical simulation.     

Dissipative solitons in quantum dot lasers

The spatiotemporal dynamics of radiation in wide-aperture semiconductor quantum-dot lasers is studied analytically and numerically. It was found that the choice of relatively rapid amplifying layers with quantum dots of a small size and slow absorbing layers with a maximal rate of exciton capture from wetting layers is optimal for the stability of spatial dissipative solitons in a single-longitudinal-mode laser. A large relaxation time of the slow absorber was found to result in a substantial decrease in the sensitivity of solitons to the tilt of the mirrors, which increases their stability and gives real chances of the experimental revealing of laser solitons.     

Diffusion-induced deflection and the effect of two-wave mixing gain on dissipative photovoltaic solitons

In an open-circuit dissipative photovoltaic (PV) crystal, by considering the diffusion effect, the deflection of bright dissipative photovoltaic (DPV) solitons has been investigated by employing numerical technique and perturbational procedure. The relevant results show that the centre of the optical beam moves along a parabolic trajectory, while the central spatial-frequency component shifts linearly with the propagation distance; furthermore, both the spatial deflection and the angular derivation are associated with the photovoltaic field. Such DPV solitons have a fixed deflection degree completely determined by the parameters of the dissipative system. The small bending cannot affect the formation of the DPV soliton via two-wave mixing.     

Dissipative solitons with energy and matter flows: Fundamental building blocks for the world of living organisms

We consider a combined model of dissipative solitons that are generated due to the balance between gain and loss of energy as well as to the balance between input and output of matter. The system is governed by the generic complex Ginzburg–Landau equation, which is coupled to a common reaction–diffusion (RD) system. Such a composite dynamical system may describe nerve pulses with a significant part of electromagnetic energy involved. We present examples of such composite dissipative solitons and analyse their internal balances between energy and matter generation and dissipation.     

Motion of molecular dissipative solitons in oriented linear <Emphasis Type="Italic">J</Emphasis> aggregates upon oblique incidence of exciting laser radiation

Motion of dissipative solitons in a molecular chain resonantly excited by laser radiation obliquely incident on the chain is computer simulated. The soliton motion with the velocity proportional to the small inclination angle is demonstrated.     

Dissipative Solitons in the Complex Ginzburg-Landau Equation for Femtosecond Lasers

We consider the models of generating femtosecond radiation in solid-state lasers with passive mode locking. An approach in which ultrashort laser pulses (USPs) are associated with the complex Ginzburg-Landau equation (GLE) is developed. The structure of solitons and the range of parameters of their existence are analytically determined and the stability criteria of those solitons are formulated for a number of limiting cases. The scenarios of the cyclic spectral and temporal dynamics of dissipative solitons due to the instability of the background field are studied.