- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Regular perturbation on the group-velocity dispersion parameter for nonlinear fibre-optical communications
摘要： Communication using the optical fibre channel can be challenging due to nonlinear effects that arise in the optical propagation. These effects represent physical processes that originate from light propagation in optical fibres. To obtain fundamental understandings of these processes, mathematical models are typically used. These models are based on approximations of the nonlinear Schr?dinger equation, the differential equation that governs the propagation in an optical fibre. All available models in the literature are restricted to certain regimes of operation. Here, we present an approximate model for the nonlinear optical fibre channel in the weak-dispersion regime, in a noiseless scenario. The approximation is obtained by applying regular perturbation theory on the group-velocity dispersion parameter of the nonlinear Schr?dinger equation. The proposed model is compared with three other models using the normalized square deviation metric and shown to be significantly more accurate for links with high nonlinearities and weak dispersion.
关键词： group-velocity dispersion,nonlinear fibre-optical communications,regular perturbation theory,nonlinear Schr?dinger equation
更新于2025-09-23 15:19:57
-
Breather and Solitons Waves in Optical Fibers via Exponential Time Differencing Method
摘要： This work proposes the numerical solutions of the cubic nonlinear Schr?dinger equation subjected to rational initial value for three cases, (i) Akhmediev breather (ii) Peregrine and (iii) Kuznetsov-Ma solitons by operating exponential time differencing method (ETDM). The work shows that ETDM is a reliable and accurate method to find the solutions comparing to Adomian decomposition method (ADM) and Laplace-Adomian decomposition method (LADM).
关键词： Exponential Time Differencing Method,Akhmediev breather,Kuznetsov-Ma soliton,Peregrine soliton,Nonlinear Schr?dinger equation
更新于2025-09-23 15:19:57
-
Periodic soliton interactions for higher-order nonlinear Schr??dinger equation in optical fibers
摘要： Research on the interactions between optical solitons is of great significance for the large capacity and long distance transmission in optical fibers. In this paper, interactions between periodic solitons are investigated for the first time. Analytic solution for the high-order nonlinear Schr?dinger equation, which can be used to describe the periodic soliton transmission, is obtained based on the bilinear method. Interaction characteristics between periodic solitons are discussed. Influences of corresponding dispersion and nonlinear effects on their interactions are analyzed. Results provide theoretical guidance for the stable transmission of periodic solitons in inhomogeneous optical fibers.
关键词： Solitons,Nonlinear Schr?dinger equation,Inhomogeneous optical fiber,Soliton interaction
更新于2025-09-23 15:19:57
-
On the Nonlinear Schr?dinger Equation with a Variable Damping Term
摘要： We consider the L2-critical nonlinear Schr?dinger equation with an inhomogeneous damping coefficient a(x). We prove the global existence of the solution in H 1(Rd) and we give the minimal time of the blow up for some initial data.
关键词： Damped nonlinear Schr?dinger equation,global existence,blow-up
更新于2025-09-19 17:15:36
-
Multiple filamentation and control of properties of self-guided elliptical Gaussian laser beam
摘要： The spatial evolution of an elliptical Gaussian beam in fluoride glass (Kerr medium) is studied using nonlinear Schro¨dinger equation solved by split-step beam propagation method. Solutions obtained by numerical simulation are analysed to study the effect of variation of input beam ellipticity on the process of multiple ?lamentation in elliptical Gaussian beam, where emphasis is on the properties of the self-guided Gaussian laser beam by externally induced input beam astigmatism. Controlling the properties of self-guided laser beam is a necessity in generation of tailored ?laments.
关键词： Multiple ?lamentation,Nonlinear Schrodinger equation (NLSE),Tailored ?laments,Beam ellipticity
更新于2025-09-16 10:30:52
-
Multicore-fiber solitons and laser-pulse self-compression at light-bullet excitation in the central core of multicore fibers
摘要： The propagation of laser pulses in multicore fibers (MCFs) made of a central core and an even number of cores located in a ring around it is studied. Approximate quasisoliton homogeneous solutions of the wave field in the MCF considered are found. The stability of the in-phase soliton distribution is shown analytically and numerically. At low energies, its wave field is distributed over all MCF cores and has a duration that exceeds the duration of the nonlinear Schr?dinger equation (NSE) soliton with the same energy by many (i.e., five to six) times. In contrast, almost all of the radiation at high energies is concentrated in the central core with a duration similar to the NSE soliton. The transition between the two types of distributions is very sharp and occurs at a critical energy, which is weakly dependent on the number of cores and on the coupling coefficient with the central core. The self-compression mechanism of laser pulses was proposed. It consists in injecting such MCFs with a wave packet being similar to the found soliton and having an energy larger than the critical value. It is shown that the compression ratio depends weakly on the energy and the number of cores and is approximately equal to six times with an energy efficiency of almost 100%. The use of longer laser pulses allows one to increase the compression ratio up to 30–40 times with an energy efficiency of more than 50%. The obtained analytical estimates of the compression ratio and its efficiency are in good agreement with the results of a numerical simulation.
关键词： light-bullet excitation,laser-pulse self-compression,nonlinear Schr?dinger equation,multicore fibers,solitons
更新于2025-09-16 10:30:52
-
Simulation of generation of ultrashort pulses in a laser based on the nonlinear polarisation evolution in two segments of a polarisation-maintaining fibre
摘要： A model describing generation of ultrashort optical pulses in a fibre cavity with Kerr nonlinearity and normal dispersion is constructed based on numerical solution of a nonlinear Schr?dinger equation. The model makes it possible to investigate the specific features of pulsed generation of a passively mode-locked laser based on the effect of nonlinear polarisation evolution (NPE) in two segments of a polarisation-maintaining (PM) fibre. It is shown theoretically that the proposed scheme may provide generation of linearly chirped optical pulses with a spectral width of above 25 nm and a centre wavelength of 1030 nm.
关键词： nonlinear Schr?dinger equation,fibre laser,ultrashort pulses,passive mode locking
更新于2025-09-16 10:30:52
-
Nonlinear Optics - Novel Results in Theory and Applications || Nonlinear Schr?dinger Equation
摘要： Firstly, based on the small-signal analysis theory, the nonlinear Schrodinger equation (NLSE) with fiber loss is solved. It is also adapted to the NLSE with the high-order dispersion terms. Furthermore, a general theory on cross-phase modulation (XPM) intensity fluctuation which adapted to all kinds of modulation formats (continuous wave, non-return-to-zero wave, and return-zero pulse wave) is presented. Secondly, by the Green function method, the NLSE is directly solved in the time domain. It does not bring any spurious effect compared with the split-step method in which the step size has to be carefully controlled. Additionally, the fourth-order dispersion coefficient of fibers can be estimated by the Green function solution of NLSE. The fourth-order dispersion coefficient varies with distance slightly and is about 0.002 ps4/km, 0.003 ps4/nm, and 0.00032 ps4/nm for SMF, NZDSF, and DCF, respectively. In the zero-dispersion regime, the higher-order nonlinear effect (higher than self-steepening) has a strong impact on the short pulse shape, but this effect degrades rapidly with the increase of β2. Finally, based on the traveling wave solution of NLSE for ASE noise, the probability density function of ASE by solving the Fokker-Planck equation including the dispersion effect is presented.
关键词： small-signal analysis,traveling wave solution,Fokker-Planck equation,Green function,nonlinear Schrodinger equation
更新于2025-09-12 10:27:22
-
Experimental realization of Fermi-Pasta-Ulam-Tsingou recurrence in a long-haul optical fiber transmission system
摘要： The integrable nonlinear Schr?dinger equation (NLSE) is a fundamental model of nonlinear science which also has important consequences in engineering. The powerful framework of the periodic inverse scattering transform (IST) provides a description of the nonlinear phenomena modulational instability and Fermi-Pasta-Ulam-Tsingou (FPUT) recurrence in terms of exact solutions. It associates the complex nonlinear dynamics with invariant nonlinear spectral degrees of freedom that may be used to encode information. While optical fiber is an ideal testing ground of its predictions, maintaining integrability over sufficiently long distances to observe recurrence, as well as synthesizing and measuring the field in both amplitude and phase on the picosecond timescales of typical experiments is challenging. Here we report on the experimental realization of FPUT recurrence in terms of an exact space-time-periodic solution of the integrable NLSE in a testbed for optical communication experiments. The complex-valued initial condition is constructed by means of the finite-gap integration method, modulated onto the optical carrier driven by an arbitrary waveform generator and launched into a recirculating fiber loop with periodic amplification. The measurement with an intradyne coherent receiver after a predetermined number of revolutions provides a non-invasive full-field characterization of the space-time dynamics. The recurrent space-time evolution is in close agreement with theoretical predictions over a distance of 9000 km. Nonlinear spectral analysis reveals an invariant nonlinear spectrum. The space-time scale exceeds that of previous experiments on FPUT recurrence in fiber by three orders of magnitude.
关键词： finite-gap solutions,nonlinear Schr?dinger equation,nonlinear spectral analysis,Fermi-Pasta-Ulam-Tsingou recurrence,optical fiber transmission
更新于2025-09-12 10:27:22
-
On the role of four-wave mixing effect in the interactions between nonlinear modes of coupled generalized nonlinear Schr?dinger equation
摘要： In this paper, we investigate the effect of four-wave mixing in the interactions among nonlinear waves such as solitons, breathers, and rogue waves of a coupled generalized nonlinear Schr?dinger equation. We explore several interesting results including superposition of breather pulses, increment in the number of breather pulses and in amplitudes of breathers, and rogue waves. By strengthening the four-wave mixing parameter, we observe different transformations that occur between different localized structures. For instance, we visualize a transformation from bright soliton to breather form, bright and dark rogue wave to four-petaled rogue wave structures, four-petaled rogue wave to other rogue wave forms, and so on. Another important observation that we report here is that the interaction of a bright soliton with a rogue wave in the presence of the four-wave mixing effect provides interaction between a dark oscillatory soliton and a rogue wave.
关键词： solitons,coupled generalized nonlinear Schr?dinger equation,breathers,four-wave mixing,rogue waves,nonlinear waves
更新于2025-09-12 10:27:22