- 标题
- 摘要
- 关键词
- 实验方案
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Effect of recovery time of nonlinear absorber saturated losses on the soliton pulse structure in a fibre laser with different cavity lengths
摘要： Using numerical simulation methods, we have calculated the dependences of the pulse profile and spectrum of a ring fibre laser in the region of anomalous group velocity dispersion on the length of the laser cavity and the recovery time of the nonlinear absorber saturated losses. It is found that with increasing cavity length the laser pulse acquires a pedestal, the positions of its edges corresponding to the frequencies of the Kelly sidebands. It is shown that the finiteness of the recovery time of the saturable absorber leads to an asymmetry in the profile and spectrum of the laser pulse.
关键词： recovery time,saturable losses,Kelly sidebands,soliton fibre laser,nonlinear saturable absorber
更新于2025-09-16 10:30:52
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Three-component coupled nonlinear Schr??dinger equation: Optical soliton and modulation instability analysis
摘要： This study successfully extracts the combined dark-bright and singular optical solitons to the three-component nonlinear Schr¨odinger equation by using the extended sinh-Gordon equation expansion method. The modulation instability analysis of the governing model is also presented. By using suitable values of the parameters, the 2-, 3-dimensional, and contour graphs to the reported results and the gain spectrum for the modulation instability analysis are plotted.
关键词： Optical soliton,Modulation Instability,Three-component NLSE
更新于2025-09-16 10:30:52
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Nondegenerate soliton solutions in certain coupled nonlinear Schr?dinger systems
摘要： In this paper, we report a more general class of nondegenerate soliton solutions, associated with two distinct wave numbers in different modes, for a certain class of physically important integrable two component nonlinear Schr?dinger type equations through bilinearization procedure. In particular, we consider coupled nonlinear Schr?dinger (CNLS) equations (both focusing as well as mixed type nonlinearities), coherently coupled nonlinear Schr?dinger (CCNLS) equations and long-wave-short-wave resonance interaction (LSRI) system. We point out that the obtained general form of soliton solutions exhibit novel profile structures than the previously known degenerate soliton solutions corresponding to identical wave numbers in both the modes. We show that such degenerate soliton solutions can be recovered from the newly derived nondegenerate soliton solutions as limiting cases.
关键词： Degenerate bright soliton solutions,Coupled nonlinear Schr?dinger systems,Hirota bilinear method,Nondegenerate bright soliton solutions
更新于2025-09-12 10:27:22
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Real-time dynamics of soliton collision in a bound-state soliton fiber laser
摘要： We experimentally investigated the soliton collisions between soliton molecules and deuterogenic solitons spontaneously generated on the continuous wave (cw) noise background in an ultrafast erbium-doped fiber laser mode locked with MoS2 saturable absorber (SA). The dynamics of the soliton collisions were observed using the time-stretch dispersion Fourier transform technique. The noise-induced deuterogenic solitons first undergo spectral broadening and wavelength shifting, then collide successively with a soliton molecule and eventually vanish. Within the simple collision framework, the spectral-temporal dynamics of soliton collision would help to unveil the self-stabilization mechanism of the soliton molecules in consideration of dispersive wave shedding. This nonlinear dynamics is similar to the soliton rain, except that complex condensed soliton phase is substituted with a soliton molecule.
关键词： time-stretch dispersive Fourier transform.,soliton molecule,molybdenum disulfide,soliton collision
更新于2025-09-12 10:27:22
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All fiber mode-locked thulium-doped fiber laser using a novel femtosecond-laser-inscribed 45°-plane-by-plane-tilted fiber grating
摘要： Using the novel 45°-plane-by-plane-tilted fiber grating inscribed by a femtosecond laser as an in-line fiber polarizer, we demonstrate an all-fiber passively mode-locked thulium-doped fiber laser. We characterize the grating for polarization-dependent loss, indicating high contrast and broad operating wavelength. The 45°-tilted fiber grating together with polarization controller act as an artificial saturable absorber suitable for mode-locking through nonlinear polarization rotation. By properly pre-adjusting the polarization controller, stable mode-locking is achieved for a pump power in the range of 300 mW–400 mW at 1565 nm. Owing to the net anomalous dispersion, a stable mode-locked soliton pulse centered at 1870 nm with a pulse width of 862 fs is reported at a fundamental repetition rate of 22.34 MHz. A long-term stability test reveals that the laser is quite stable for 24 h under laboratory conditions, confirming the capabilities of the 45°-tilted fiber grating for stable laser operation.
关键词： fibre lasers,tilted fiber Bragg grating,dissipative soliton,thulium doped fibre,soliton mode-locking
更新于2025-09-12 10:27:22
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Stochastic Soliton Quantization in Mode-Locked Fibre Laser
摘要： Soliton quantization is a natural, intrinsic and random consequence property of localized pulses in nonlinear systems. It is formed in the fiber laser in the form of dissipative solitons due to the gain competition between the solitons in the laser cavity. The observation of quantized separations between the solitons was predicted either due to the interaction between far separated solitons or due to the interaction between weakly overlapping pulses [1, 2]. It was first found experimentally in a nonlinear amplified loop mirror mode-locked fiber laser [3] and then in a nonlinear polarization rotation mode locking fiber laser [4, 5] with a requirement of high pump power of >400 mW. Here, we report for the first time the experimental demonstration of the stochastic temporal soliton quantization state regimes at a low range of the pump powers (~41 mW) using a carbon nanotube’s saturable absorber mode-locked fiber laser [6]. We found that the regimes and the total number of pulses in the cavity are highly sensitive to the pump power and the state of the polarization which could lead to several distinct regimes of pulse formation. However, for certain pumping powers which were 41 mW and specific orientation of the laser cavity polarization controller (PC), we observed pulse trains of several tenths of pulses as shown in the real-time spatiotemporal measurements in Fig. 1a. The pulse train consists of a stochastic quantized distribution with separation between pulses starting from about 3 ns to tenths of ps with a nonlinearly quantized separation, behaving between the localized soliton pulses as shown in Fg. 1b. The pulses are localized with a much broader temporal separation far from the main soliton pulse and condensed to a very narrow seperations nearer to it. By slightly increasing the pump power to ~88 mW and varying the PC, we obtained the second order of the stochastic soliton which also have a quantized temporal distribution without any undesirable distribution of types or interactions between neighboring solitons along 5000 roundtrip pulse train. The quantized soliton, actually, has formed intrinsically in the form of dissipative solitons due to large binding soliton states.
关键词： Soliton quantization,stochastic soliton,carbon nanotube saturable absorber,mode-locked fibre laser
更新于2025-09-12 10:27:22
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Direct Observation of Intracavity Pulse Dynamics in All-Normal Dispersion All-Fiber Oscillator
摘要： Ultrafast science and technology depend strongly on the development of novel ultrafast sources, thus good understanding of nonlinear phenomena in such systems is of essence. In this paper, we present the experimental observation and theoretical analysis of various pulse dynamics in all-normal dispersion cavity producing dissipative soliton pulses. We report the results of an extensive study regarding the Stimulated Raman Scattering (SRS) process, which creates a main upper limitation for the pulse energy achievable from all-normal dispersion fiber oscillators. We report the measurements of real-time, single shot spectra registered using Dispersive Fourier Transform (DFT) technique together with measured averaged spectral phase of the pulses generated from an all-PM-fiber oscillator mode-locked with Nonlinear Optical Loop Mirror (NOLM). It is found that NOLM parameters directly influenced the pulse stability and dynamics. The Yb-doped fiber was used as an active medium and Dissipative Soliton (DS) pulses centered at 1030 nm were generated together with Stokes radiation shifted by 440 cm-1 (centered approximately at 1078 nm) produced in SRS process. The light generated in SRS process was suppressed from round-trip to round-trip by a narrow pass-band spectral filter centered at 1030 nm placed inside the laser cavity. We present the broad experimental study of ultrashort pulse dynamics with strong presence of SRS process. Spectral intensity correlation maps were calculated to describe how the SRS process disturbs the ultrashort pulse during propagation in the cavity (Fig. 1). The intensities of longer wavelengths (1040 – 1050 nm) in the pulse spectrum were destabilized due to the SRS process. In normal dispersion fiber Stokes SRS components have higher group velocity than the pulse spectral components. For positively chirped pulse SRS affects only the leading edge of the pulse which is manifested as negative correlation (Fig. 1(c)). The phenomena of repetitive partial dissipative soliton explosions and bistability of the pulse operation in an all-PM-fiber all-normal dispersion oscillator cavity were investigated as well. The clear signature of bistable operation was the hysteresis of the laser pulse power versus input pump power. Furthermore, we registered significant differences between the measured pulses spectral phases for each case. Another set of measurements was performed to analyze the pulse self-starting dynamics. We present the experimental study and numerical simulations of DS pulse dynamics in an all-normal dispersion all-fiber cavity. The numerical simulations were performed using the standard split-step Fourier-transform method employing the multi-vibrational model of SRS. DS lasers are important pulse sources and an effective platform to investigate the pulse dynamics and nonlinear processes inside the all-fiber cavities.
关键词： spectral intensity correlation maps,Yb-doped fiber,dissipative soliton pulses,Dispersive Fourier Transform,split-step Fourier-transform method,Nonlinear Optical Loop Mirror,Stimulated Raman Scattering,ultrafast science
更新于2025-09-12 10:27:22
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Soliton-Plasma Interactions and Dispersive-Wave Emission Beyond Two-Photon Resonances in Gas-Filled Hollow Capillary Fibres
摘要： Recently we have demonstrated soliton effects at high energy (0.3 mJ) in helium- and neon-filled hollow capillary fibres (HCF) [1]. We observed pulse self-compression to single-cycle durations and the generation of deep (DUV) and vacuum ultraviolet (VUV) radiation at record energy levels for a tunable source. Here, we demonstrate that soliton dynamics in capillary fibres can also be accessed with argon- and krypton-filled HCF, although ionisation effects then start to play a larger role. We also find that the DUV and VUV generation through resonant dispersive-wave (RDW) emission can be achieved at wavelengths considerably shorter than the two-photon resonances in each gas—something surprising, given previous work in gas-filled photonic crystal fibres HC-PCF [2], where soliton-related effects have been previously extensively explored at μJ pulse energy levels [3].
关键词： two-photon resonances,soliton-plasma interactions,dispersive-wave emission,gas-filled hollow capillary fibres
更新于2025-09-12 10:27:22
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Complexity in Biological and Physical Systems - Bifurcations, Solitons and Fractals || Self-Organization, Coherence and Turbulence in Laser Optics
摘要： In the last decades, rapid progress in modern nonlinear science was marked by the development of the concept of dissipative soliton (DS). This concept is highly useful in many different fields of science ranging from field theory, optics, and condensed matter physics to biology, medicine, and even sociology. This chapter aims to present a DS appearance from random fluctuations, development and growth, the formation of the nontrivial internal structure of mature DS and its breakup, in other words, a full life cycle of DS as a self-organized object. Our extensive numerical simulations of the generalized cubic-quintic nonlinear Ginzburg-Landau equation, which models, in particular, dynamics of mode-locked fiber lasers, demonstrate a close analogy between the properties of DS and the general properties of turbulent and chaotic systems. In particular, we show a disintegration of DS into a noncoherent (or partially coherent) multisoliton complex. Thus, a DS can be interpreted as a complex of nonlinearly coupled coherent “internal modes” that allows developing the kinetic and thermodynamic theory of the nonequilibrious dissipative phenomena. Also, we demonstrate an improvement of DS integrity and, as a result, its disintegration suppression due to noninstantaneous nonlinearity caused by the stimulated Raman scattering. This effect leads to an appearance of a new coherent structure, namely, a dissipative Raman soliton.
关键词： dissipative solitons,chaos in nonlinear optical systems,generalized cubic-quintic nonlinear Ginzburg-Landau equation,dissipative Raman soliton,optical turbulence
更新于2025-09-12 10:27:22
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The <i>N</i> ‐coupled higher‐order nonlinear Schr?dinger equation: Riemann‐Hilbert problem and multi‐soliton solutions
摘要： In this work, the Riemann-Hilbert (RH) problem of the N-coupled high-order nonlinear Schr?dinger (N-CHNLS) equations is studied carefully, which controls the propagation of N fields with all high-order effects such as high-order dispersion, self-steepening effect, and Raman scattering in optical fiber. The spectral analysis of the Lax pair associated with a (2N + 1) × (2N + 1) matrix spectral problem for the N-CHNLS equations is firstly carried out, from which a kind of RH problem is structured. Then a series of multi-soliton solutions including breather, bright, and dark solutions for the N-CHNLS equations can be formulated by the RH problem with the reflection-less case. In addition, with N = 4 taken as an example, the propagation behavior of these solutions and their interactions are presented by selecting appropriate parameters with some graphics.
关键词： N-coupled high-order nonlinear Schr?dinger equations,multi-soliton solutions,matrix spectral,Riemann-Hilbert problem,spectral analysis
更新于2025-09-12 10:27:22