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We investigate the propagation characteristics of two temporally separated soliton pulses with the same spectra, under the influence of stimulated Raman scattering, within a single-mode optical fiber. This analysis explores the behavior of the interacting solitons while propagating in different chalcogenide materials, exhibiting new features and promising prospects for soliton transmission in optical communication systems. Our study included all the interaction parameters constituting the nonlinear Schrödinger equation (NLSE). We have examined the relationship between the Kerr nonlinearity, interpulse and intrapulse Raman effects, and material-dependent collision length featuring a key aspect in logic design and phase control in mode-locking systems. We have also systematically shown the manifestation of the Raman response function from the Raman gain curve, which our mathematical model (the Lorentzian model) provides, that exhibits a near agreement with experimental data. Our findings reveal significant differences from the typical behavior of two-soliton interaction only due to Kerr nonlinearity. Furthermore, we have investigated the mechanism of the net energy transfer between the interacting solitons as an integral phenomenon involved in multiple soliton propagation. These results provide an insightful understanding of the associated nonlinear effects in high-power soliton transmission systems and are foreseen to possess the potential for designing advanced optical switches and mode-locked lasers. [ABSTRACT FROM AUTHOR]

As the need for compact, cost‐effective, and reliable laser sources continues to rise, fiber lasers have gained widespread interest in science and technology. In recent years, passively mode‐locked fiber lasers (PMLFLs) have emerged as pivotal tools for generating ultrashort pulses, propelling advancements across various domains including communication, manufacturing, medicine, defense, and security. Amongst the various types of lasing states supported by a PMFL, the emphasis in this review is on the noise‐like pulses (NLP) and their potential applications in supercontinuum generation (SCG). Interestingly, the quasi‐stationary operation of the NLP envelope containing numerous chaotic sub‐pulses has facilitated relatively high energy and broad bandwidth compared to standard mode‐locked laser pulses. Moreover, the NLP generation goes beyond a specific cavity arrangement, the nature of mode‐locking or cavity dispersion. Therefore, through this review, the foremost aim is to report the differences in NLPs across various experimental settings reported so far and highlight the strategies beneficial for high‐energy and broadband NLP development directly from a fiber oscillator. Secondly, the application of NLP as a seed laser is examined to stimulate SCG in different types of fibers, underlining the improved supercontinuum characteristics over the conventional ultrashort pulse pumping schemes. Finally, the benefit of NLP‐seeded SCG for various bio‐medical and industrial applications are highlighted, thanks to the broader and flatter continuum achievable through compact experimental settings. [ABSTRACT FROM AUTHOR]

Mode‐locked lasers are prone to exhibit a wide range of dynamics, including the coherent dissipative soliton with high robustness or the possible emission of incoherent pulse bursts. Herein, it is proposed to expand the notion of dissipative breathing solitons to incoherent localized formation, which is illustrated experimentally by reporting original coherent and incoherent breathing solitons generated in a 2 μm bidirectional ultrafast fiber laser. A real‐time spectral characterization of the breathing soliton dynamics with different coherence is provided, highlighting salient features of the self‐organization. The switching between coherent breathing soliton and noise‐like pulse is also experimentally demonstrated, corresponding to the multiple transient decoherence and coherence recovery. High behavior similarity exists in bidirectional solitons evolution owing to the common gain and loss modulation. Numerical simulations using a discrete laser model validate the experimental findings. This research generalizes previous observations of breathing solitons made in the coherent case and opens up new possibilities for generating breathers in various dissipative systems. [ABSTRACT FROM AUTHOR]

Ultrafast fiber lasers (UFLs) have become an attractive alternative to solid‐state lasers (SSL) due to their excellent beam quality, compactness, environmental stability, and easy thermal management. In the last decade, a significant research effort is spent to identify UFL architectures providing pulse energy, duration, and peak power comparable to those of complex and expensive, Ti:sapphire laser systems and semiconductor saturable absorber mirrors mode‐locked, Yb‐doped SSL. Lately, Mamyshev oscillators (MOs), relying on offset spectral filtering combined with nonlinear spectral broadening by self‐phase modulation, emerge as a promising solution and are rapidly becoming the state of the art for high energy/peak power UFLs based on large‐mode‐area (LMA) fibers. The focus of this work is the first demonstration of starting of the mode‐locking regime in an LMA MO with an affordable passively Q‐switched microchip laser. This solution was previously demonstrated only in low‐power MO based on single‐mode fibers, which are intrinsically easier to seed, if compared to high‐gain LMA UFLs, because of the lower amplified spontaneous emission noise floor. This starting technique in an easy‐to‐implement ring LMA MO at 1 μm is tested. The oscillator provides ≈50 nJ pulses at 12 MHz repetition rate with a minimum pulse duration of ≈50 fs after compression, resulting in MW peak power. [ABSTRACT FROM AUTHOR]

Mixed lead–tin halide perovskites, as highly sensitive materials in the near-infrared region, hold significant potential for optoelectronic device applications. Here, mixed lead–tin halide perovskite saturable absorbers (SAs) have been developed by coupling with the side-polished surfaces of the single-mode fibers and excellent saturable absorption effects of the mixed lead–tin halide perovskite SAs have been demonstrated in the near-infrared region. By constructing the in-gap site assisted carrier transfer mode, the saturation absorption process of the mixed lead–tin halide perovskite SAs can be well explained, in which defects as in-gap sites can help the photon-generated carriers transfer into the conduction band and promote the Pauli-blocking-induced absorption bleaching in the SA. Moreover, ytterbium-doped fiber lasers based on perovskite SAs have been fabricated, and mode-locked operations at 1040 nm are achieved using the mixed lead–tin halide perovskite SA, generating ultra-short pulses with a pulse width of 683 fs, 3 dB bandwidth of 4.88 nm, signal-to-noise ratio exceeding 49.74 dB, and a repetition rate of 3.74 MHz. Our findings demonstrate that the mixed lead–tin halide perovskite SAs have excellent optical modulation capability and promising applications in the field of ultrafast photonics. [ABSTRACT FROM AUTHOR]

Ultrafast fiber lasers constitute a flexible platform to investigate new solitary wave concepts. To surpass the low energy limitation of the conventional solitons generated in standard telecom fibers, successive breakthroughs have promoted the usage of an important frequency chirping within fiber oscillators. This lead to original solitary wave regimes such as stretched-pulse, all-normal-dispersion, and self-similar dynamics. We here revisit ultrafast fiber lasers built from standard optical fibers featuring solely anomalous dispersion. We propose a new cavity design enhancing key dissipative effects with contained frequency chirping and demonstrate the generation of high energy pulses in the few-picoseconds regime. The involved intracavity dynamics blends conventional and dissipative soliton features in an unseen way with low- and high-energy propagation regions, allowing an increased flexibility and novel scalability prospects. The authors revisit ultrafast fiber lasers with anomalous dispersion to propose a new laser design enhancing dissipative effects. Their approach yields high-energy few-picosecond pulses, blending soliton features for improved flexibility and scalability. [ABSTRACT FROM AUTHOR]

The linewidth enhancement factor (LWEF) of a semiconductor optical amplifier (SOA) quantifies refractive index fluctuations in the gain medium, which induce phase distortion in the amplified optical signal. Optoelectronic systems employing SOAs with high LWEFs often exhibit poor device stability and beam coherence. Thus, designing SOAs with low LWEF is imperative. Recently, Quantum-Dot (QD) SOAs have emerged as a solution for LWEF suppression due to quantum-confinement effects enabling tunability of the QD carrier density and emission frequency. In this study, we aim to design a composite active region comprised of a host medium and the embodied QDs, to explore the corresponding LWEF variation and propose the ultimate design strategy to achieve near-zero LWEF in QD SOAs for enhancing device stability and beam coherence. Our approach entails modeling the refractive index of the composite active region using effective medium approximation via Maxwell–Garnett mixing formulation. We then extensively tune key SOA parameters, including QD carrier density, QD emission frequency, and the collision-time constant of the carriers to uncover the optimal configuration for minimizing the LWEF. Based on empirical values, we have developed and validated a simple yet effective algorithm that precisely simulates LWEF behavior in response to changes in key QD SOA parameters. This approach offers a straightforward model for estimating LWEF variation, and its corresponding minimization in QD SOAs without requiring complex experimental measurement techniques. [ABSTRACT FROM AUTHOR]

In this work, a V2AlC‐based saturable absorber (SA) was applied to a 2 μm band passively mode‐locked (PML) laser. The saturation intensity and modulation depth of the V2AlC‐based SA were detected by the I‐scan method, which were 225.05 MW/cm2 and 7.68%, respectively. In the PML mode, an average power of 2.12 W at 1939 nm and a pulse width of 1077 ps at 82.49 MHz were obtained from the Tm:YAP laser. In addition, the laser exhibited a good beam quality factor (M2) which was measured to be less than 1.2. These results will pave the way for the application of V2AlC‐based SA in ultrafast lasers. [ABSTRACT FROM AUTHOR]

Coherent mode locking is based on the formation of 2 π pulses of self-induced transparency in the absorbing medium and π pulses in the amplifying medium. In this regime it becomes possible to generate ultrashort laser pulses down to one oscillation cycle with a pulse duration being much shorter than the polarization relaxation time T 2 of the amplifying and absorbing medium. In this article a two-section laser model with a ring resonator based on absorbing and amplifying medium with short relaxation times has been applied. We have demonstrated a self-starting regime of coherent mode locking with picosecond and femtosecond laser pulses using numerical simulations for the given model. In addition, we have shown that there is a significant influence of generation frequency detuning on laser pulse duration and intensity. Moreover, we have compared our numerical results with an analytical model of a coherent mode-locked laser based on the area theorem. We believe that the findings of this work can open a pathway towards the practical application of mode locking in mid-IR and THz quantum cascade lasers. [ABSTRACT FROM AUTHOR]

Pulsed solid‐state lasers comprise 2D materials as saturable absorbers that contain transparent windows of the atmosphere and characteristic fingerprint spectra of several vital molecules that are significant in various applications and research. Over the past few decades, significant progress has been made in the development of narrow pulse width, high energy, high average output power, high efficiency, and simple construction of passively Q‐switched and mode‐locked lasers with 2D materials as saturable absorbers. This review summarizes the development of 2D materials, including graphene, transition metal dichalcogenides, black phosphorus, topological insulators, and MXenes, as modulator devices for solid‐state lasers owing to their broadband operation, excellent nonlinear optical response, low recovery time, ultrafast dynamic processing, and easy fabrication. Then, some new emerging and representative applications of pulsed solid‐state lasers are introduced and illustrated such as laser surgery, material processing, and lidar. Finally, future challenges and perspectives of pulsed solid‐state lasers with 2D materials‐based saturable absorbers are analyzed and addressed. The rapid development of pulsed solid‐state lasers with the continuous improvement of modulation technology is expected to expand opportunities for application in industry, scientific, medical, and other areas. [ABSTRACT FROM AUTHOR]

Frequency comb spectroscopy and field-resolved broadband absorption spectroscopy are promising techniques for rapid, precise, and sensitive detection of short-lived atmospheric pollutants on-site. Enhancing detection sensitivity in absorption spectroscopy hinges on bright sources that cover molecular resonances and fast signal modulation techniques to implement lock-in detection schemes efficiently. Yb:YAG thin-disk lasers, combined with optical parametric oscillators (OPOs), present a compelling solution to fulfill these requirements. In this work, we report on a bright OPO pumped using a Yb:YAG thin-disk Kerr-lens mode-locked oscillator delivering 2.8 W, 114 fs pulses at 2.06 μm with an averaged energy of 90 nJ. The OPO cavity operates at 30.9 MHz repetition rate—twice the repetition rate of the pump laser—allowing for a broadband, efficient, and dispersion-free modulation of the OPO output pulses at a 15.45 MHz rate. With 13% optical-to-optical conversion efficiency and a high-frequency intra-cavity modulation, this scalable scheme holds promise to advance the detection sensitivity and frontiers of field-resolved spectroscopy. [ABSTRACT FROM AUTHOR]

Transverse mode control of laser intracavity oscillation is crucial for generating high-purity cylindrical vector beams (CVBs). We utilized the mode conversion and mode selection properties of two-mode long-period fiber gratings (TM-LPFGs) and two-mode fiber Bragg gratings (TM-FBGs) to achieve intracavity hybrid-mode oscillations of LP01 and LP11 from an all-few-mode fiber laser. A mode-locked pulse output with a repetition rate of 12.46 MHz and a signal-to-noise ratio of 53 dB was achieved with a semiconductor saturable absorber mirror (SESAM) for mode-locking, at a wavelength of 1550.32 nm. The 30 dB spectrum bandwidth of the mode-locked pulse was 0.13 nm. Furthermore, a high-purity CVB containing radially polarized and azimuthally polarized LP11 modes was generated. The purity of the obtained CVB was greater than 99%. The high-purity CVB pulses have great potential for applications in optical tweezers, high-speed mode-division multiplexing communication, and more. [ABSTRACT FROM AUTHOR]

Artificial saturable absorbers (SA) are nonlinear optical devices widely employed in mode‐locked lasers. Among the artificial SAs are nonlinear polarization evolution (NPE) and nonlinear amplifying loop mirrors that can work in either figure‐of‐eight (Fo8) or figure‐of‐nine (Fo9) laser cavities. The NPE technique is highly sensitive to environmental perturbations. Both Fo8 and Fo9 laser cavities exhibit a higher environmental stability than the NPE technique. Here the recent advances of the Fo9 laser cavity, with a focus on the pulse formation mechanisms and the role of different cavity parameters that can enable ultrafast mode‐locking analyses are discussed. Besides, the recent development of using the Fo9 laser cavity to generate high‐energy rectangular laser pulses through either dissipative soliton resonance or noise‐like pulse regimes is also reviewed. In conclusion, the current issues and challenges of pulse formation through the Fo9 laser cavity are highlighted and recommendations for future research directions are proposed. This review is expected to provide a deeper insight into the Fo9 laser cavity as the next generation of artificial SA with interesting cavity structures, laser features, and output performances. [ABSTRACT FROM AUTHOR]

Low‐dimensional lead halide perovskites demonstrate remarkable nonlinear optical characteristics attributed to their distinctive physical structures and electronic properties. Nevertheless, the investigation into their nonlinear optical properties remains in its incipient stages. This study addresses this gap by precisely controlling solvent volumes to synthesize both 0D Cs4PbBr6 and Cs4PbBr6/CsPbBr3 perovskites. Remarkably, as saturable absorbers, both pure Cs4PbBr6 and Cs4PbBr6/CsPbBr3 composites exhibit favorable nonlinear optical properties within the C‐band, showcasing modulation depths of 9.22% and 16.83%, respectively. Moreover, for the first time, Cs4PbBr6 and Cs4PbBr6/CsPbBr3 composites have been successfully integrated into erbium‐doped fiber lasers to realize the mode‐locking operations. The utilization of the Cs4PbBr6/CsPbBr3 composites as a saturable absorber that enables the generation of conventional soliton mode‐locked laser pulses with a pulse duration of 688 fs, and a repetition frequency of 10.947 MHz at a central wavelength of 1557 nm. Cs4PbBr6 is instrumental in generating laser pulses at a frequency of 10.899 MHz, producing pulse widths of 642 fs at the central wavelength of 1531.2 nm and 1.02 ps at the central wavelength of 1565.3 nm, respectively. The findings of this investigation underscore the potential utility of 0D Cs4PbBr6 and Cs4PbBr6/CsPbBr3 composites as promising materials for optical modulation within fiber laser applications. [ABSTRACT FROM AUTHOR]

The synthesis of 2D MoWS2 nanosheets involved the liquid-phase exfoliation technique was explored in this paper. The nonlinear optical response of MoWS2 was characterized in the 1 µm wavelength range, and its suitability as a saturable absorber (SA) was confirmed. Experimental demonstrations were conducted by using MoWS2 as an SA in an idler-resonant intracavity KTA optical parametric oscillator (OPO) driven by a dual-loss-modulated Q-switched and mode-locked (QML) YVO4/Nd:YVO4 laser with an acousto-optic modulator (AOM). By appropriately tuning the pump power and the AOM repetition rate, the Q-switched envelope pulse widths for the signal and idler waves could be significantly reduced to be shorter than the cavity round-trip transit time, i.e., the interval between two neighboring mode-locking pulses. Consequently, this enabled the generation of sub-nanosecond single mode-locking pulses with a low repetition rate, high pulse energy, and remarkable stability. With a repetition rate of 1 kHz and maximal pulse energies of 318 µJ and 169 µJ, respectively, sub-nanosecond single mode-locking pulses of the signal and idler waves were generated. The theoretical model was established using coupled rate equations with a Gaussian spatial distribution approximation. The numerical simulation results for generating sub-nanosecond single mode-locking pulses for the signal and idler waves within their respective Q-switched envelopes aligned fundamentally with the experimental results, proving that MoWS2 can be a potential nanomaterial for further optoelectronic applications. [ABSTRACT FROM AUTHOR]

We present mutual optical coupling in terahertz (THz) quantum cascade wire laser arrays that are flip-chip bonded to a dielectric substrate. The mounting substrate is patterned for individual electrical contacting of each wire laser of the array. The resulting sandwich-like structure supports wire laser modes with a significant part propagating outside the cavity and mediates the long range coupling. The evanescent field part of the modes couples to the adjoining ridge, which, in turn, leads to mutual optical injection-locking between them. We demonstrate this effect for both geometrically similar and dissimilar wire lasers when biased in pulsed operation with temporally overlapping bias pulses. Finite element simulations confirm our measurement results. By applying time-shifted bias pulses to individual array elements, a controllable optical injection seeding of the wire cavity is achieved. We observe intensity modification of the laser modes with changing bias pulse overlap as a result of the injection locking. By choosing both the physical spacing of the laser ridges and the intensity of the seeding laser correctly, the relative intensities of the favored lasing modes are enhanced up to 95 percent. Understanding the coupling in THz wire laser arrays is important for future device improvements in terms of higher continuous-wave operating temperatures through better thermal dissipation, and higher output power and an improved far field due to controlled coupling of their modes. [ABSTRACT FROM AUTHOR]

Cylindrical vector beams (CVBs), which feature a unique spatially non-uniform polarization distribution with an axis symmetry, have been attracting increasing attention due to their various potential applications. However, mainstream CVB lasers demonstrated so far are emitting in the near-infrared wavelength region. The development of mid-infrared (MIR) CVB lasers can greatly broaden their application areas, especially when operating in the mode-locking regime where high peak power ultrafast pulses can be produced. Here, we present the direct generation of MIR femtosecond CVBs from an Er-doped fluoride fiber laser. The mode-locking operation is realized by the nonlinear polarization rotation technique, accompanying with an intra-cavity CVB converter based on two S-waveplates. Both radially and azimuthally polarized beams in the form of mode-locking pulse trains are achieved in the experiment with a typical pulse width of 336 fs and a peak power of 7.3 kW at a repetition of 42.24 MHz. The center wavelength locates at around 2795 nm. This work can provide a solution for the direct generation of femtosecond CVBs in the MIR wavelength region and facilitate its application in fields such as micro-manufacturing and nanoparticle manipulation. [ABSTRACT FROM AUTHOR]

In this paper, we numerically study the influence of saturable absorber parameters, namely, modulation depth, recovery time, and saturation energy, on the performance of an ultrafast fiber laser that is mode-locked by a hybrid scheme of a saturation absorber (SA) and a nonlinear polarization rotation (NPR). Maps of mode-locked states related to intracavity wave-plates are created to evaluate the operation of hybrid mode-locking under different modulation depths of the SA. Along with the improvement of modulation depth of the SA, the mode-locked pulse results from a combination effect of the SA and NPR. The numerical analysis reveals that the SA parameters can significantly impact the pulse profile, peak power, and operation state. Moreover, they can also impact the selection of NPR mode-locked points, resulting in variation in stable single pulse output. A higher modulation depth can suppress the unstable multiple pulses' operation and convert them into harmonic mode-locked pulses. The obtained results indicate that the selection of appropriate SA parameters can effectively improve the output characteristics of hybrid mode-locked fiber lasers. [ABSTRACT FROM AUTHOR]

An experimental and computational optical pump-probe model is constructed, which utilizes two ultrafast pump pulses within the repetition period of a mode-locked laser to generate electron spin polarization. This report focuses on the effects of resonant spin amplification induced by an infinite train of the two-pump pulses. The first pump pulse is used to generate ordinary resonant spin amplification spectra, while the second pump pulse is used to manipulate the generated spectra. This model gives control of the accumulation of spin polarized electrons along a magnetic field by selecting the temporal separation of the two-pump pulses. The computational model accurately predicts and agrees with the experimental results, which shows manipulation of resonant spin peaks that are no longer entirely dependent on the external magnetic field. This two-pump model and the associated manipulations of resonant spin peaks can be used as a platform to construct and conceptualize resonant spin amplification-based optospintronic devices and applications. [ABSTRACT FROM AUTHOR]

Femtosecond laser inscriptions in optical media current offer the most reliable optical technology for processing of transparent materials, among which is the laser micromachining technology. In this process, the nonlinearity of the transparent medium can be either intrinsic or induced by multiphoton ionization processes. In this work, a generic model is proposed to describe the dynamics of femtosecond laser inscription in transparent materials characterized by a saturable nonlinearity. The model takes into account multiphoton ionization processes that can induce an electron plasma of inhomogeneous density and electron diffusions. The mathematical model is represented by a one-dimensional complex Ginzburg–Landau equation with a generalized saturable nonlinearity term in addition to the residual nonlinearity related to multiphoton ionization processes, coupled to a rate equation for time evolution of the electron plasma density. Dynamical properties of the model are investigated focusing on the nonlinear regime, where the model equations are transformed into a set of coupled first-order nonlinear ordinary differential equations, which are solved numerically with the help of a sixth-order Runge–Kutta algorithm with a fixed time step. Simulations reveal that upon propagation, spatiotemporal profiles of the optical field and of the plasma density are periodic pulse trains, the repetition rates and amplitudes of which are increased with an increase of both the multiphoton ionization order and the saturable nonlinearity. When electron diffusions are taken into account, the system dynamics remains qualitatively unchanged; however, the electron plasma density gets strongly depleted, leaving almost unchanged the amplitude of pulses composing the femtosecond laser soliton crystals. [ABSTRACT FROM AUTHOR]

A narrow linewidth hybrid integrated distributed Bragg reflector (DBR) laser platform operating at 2 μm wavelength region is demonstrated. The laser architecture comprises AlGaInAsSb/GaSb type-I quantum well reflective semiconductor optical amplifiers butt-coupled to a Si3N4 photonic integrated circuit (PIC), incorporating a narrow-band DBR. The DBR is realized with a long spiral-shaped waveguide structure with periodic circular posts placed adjacent to the waveguide. At room temperature operating conditions, the laser exhibits a maximum continuous wave output power of more than 17 mW for emission near 2 μm. Linewidth properties are analyzed with a heterodyne measurement technique, involving the mixing of the laser signal with a frequency comb phase-locked to an ultra-stable laser. The hybrid laser exhibits a narrow linewidth of ∼8 kHz in 1 ms timescale and ∼50 kHz in 10 ms timescale. [ABSTRACT FROM AUTHOR]

Optical frequency combs with equidistant frequency modes have revolutionized metrology and spectroscopy. The most widespread combs consist of periodic pulse trains generated by mode-locked lasers. However, it has recently been demonstrated that most semiconductor lasers based on Fabry–Pérot cavities, such as quantum well laser diodes, quantum cascade lasers, and quantum dot lasers, can enter an unconventional regime without traditional mode-locking mechanisms. The time-domain profile of these self-locked combs features a frequency-modulated (FM) wave with quasi-continuous-wave intensity and near-linear frequency chirp. The observation of the FM mode of operation in lasers with significantly different dynamics suggested that this mode is a fundamental operating state of semiconductor lasers, stemming from a deeper underlying mechanism. Thanks to recent theoretical and experimental advances, the origin of FM behavior has become clear. In this Perspective, we discuss the current status of FM combs in semiconductor lasers based on Fabry–Pérot cavities, focusing on their physical origin, modeling, characterization, bandwidth enhancement, and potential in future applications. [ABSTRACT FROM AUTHOR]

The resolution and above all the stability of the geodetic reference frames is crucially important when global change, such as the sea level rise is observed. In this context systematic errors are still presenting a significant challenge to the measurement techniques of space geodesy. In order to overcome this unfortunate situation for the satellite laser ranging technique, we have utilized the injection of a mode-locked laser to provide a stable low-noise link between the optical domain, where the measurements are carried out, and the microwave regime in which the station clock is defined. We obtained a considerably enhanced measurement delay stability by 10–20 ps over several days, albeit with some experimental challenges. The implementation of waveform scans required us to revisit the issue of target structure and intensity variation in satellite laser ranging. [ABSTRACT FROM AUTHOR]

Solid‐state lasers based on mode‐locked technology are widely studied for their strong ability of average or peak power scaling and wide wavelength coverage. However, it usually takes a long time and a lot of effort to manually align an ultrafast solid‐state laser to achieve laser emission and stable mode‐locking. Here, an approach based on intelligent human‐like algorithms is proposed for aligning a solid‐state ultrafast laser system. The intelligent system is based on multi‐algorithm fusion and can fully simulate the process of observation, analysis, decision, and action of an experienced experimenter in the adjustment of the laser alignment and mode‐locking. The intelligent adjustment starts from the state of no laser emission, adopts the neural network, the modified augmented random search (ARS) algorithm, random search, and sliding window strategy, and takes the fluorescence and speckle patterns as indications to realize the laser emission and stable mode‐locking automatically. Several validation experiments are conducted using this intelligent system, and the stable mode‐locked pulses can be achieved within 40 s. This technology provides an efficient solution to the ultrafast solid‐state laser that requires full automatic laser emitting and stable mode‐locking for the first time. [ABSTRACT FROM AUTHOR]

Soliton pulsations are ubiquitous feature of non‐stationary soliton dynamics in mode‐locked lasers and many other physical systems. To overcome difficulties related to a huge amount of necessary computations and low efficiency of traditional numerical methods in modeling the evolution of non‐stationary solitons, a two‐parallel bidirectional long short‐term memory recurrent neural network (TP‐Bi_LSTM RNN) is proposed, with the main objective to predict dynamics of vector‐soliton pulsations (VSPs) in various complex states, whose real‐time dynamics is verified by experiments. For two examples, viz., single‐ and bi‐periodic VSPs, with period‐21 and a combination of period‐3 and period‐43, the prediction results are better than provided by direct simulations – namely, deviations produced by the TP‐Bi_LSTM RNN results are 36% and 18% less than those provided by the simulations, respectively. This means that predicted results provided by the neural network are better than numerical simulations. Moreover, the prediction results for unstable VSP state with period‐9 indicate that the optimization of training sets and the number of training iterations are particularly important for the predictability. Besides, the scheme of coded information storage based on the TP‐Bi_LSTM RNN, instead of actual pulse signals, is realized too. The findings offer new applications of deep learning to ultrafast optics and information storage. [ABSTRACT FROM AUTHOR]

The Manakov model, a framework of coupled non-linear Schrödinger equations, reflects an essential integrable model in non-linear physics, particularly used to analyze soliton behavior and wave interactions in multiple physical realms such as optical theory and plasma physics. Its distinct integrability features make it a treasure trove for investigating complex interactions between wave propagation and non-linear systems. With an emphasis on the stochastic Manakov model, this research article explores the field of stochastic partial differential equations (SPDE). This writing aims to lower the cost and time frame for experiments by using particular integration approaches to generate a wide variety of optical solitons to satisfy the said model. We complete our thrust using two innovative approaches: the Unified Ricatti Equation Algorithm which depends on the Riccati equation and its special solutions, and the New Extended Auxiliary Equation Method which builds several, more general traveling wave solutions to nonlinear partial differential equations using a more straightforward and cohesive approach. The combination of these two not only improves our capability to handle complicated SPDEs but also provides fresh perspectives on how soliton structures and stochastic effects connect within the governing model. By employing these techniques, we obtain various solitary and traveling wave solutions, including dark, singular, and bright solitons. To ensure the validity of the results, the density, contour, 3D, and 2D profiles of various attained solutions are numerically generated by selecting appropriate values for several proposed framework parameters. The presence of multiplicative white noise does not propagate to other components; it just affects the phase portion of the solitons. Research conducted on the mentioned framework involving multiplicative white noise encounters significant applications in optical communication systems. By comprehending soliton behavior and effects, we can optimize the transmission of information in optical fibers, strengthen mode-locked lasers, and advance laser-based material handling. This exclusive blend of challenging model and methodologies led to the discovery of numerous unique soliton solutions and their corresponding behaviors. [ABSTRACT FROM AUTHOR]

This study demonstrates the potential of nickel-trimesic acid, a material from the metal-organic framework (MOF) family, as a real saturable absorber (SA) for stable passively mode-locked pulse generation in erbium-doped fiber laser (EDFL) and thulium-holmium co-doped fiber laser (THDFL) ring cavities. The fabricated SA has modulation depths of 4.10% and 2.01%, and saturation intensities of 24.50 MW/cm2 and 14.50 MW/cm2, characterized at 1.56 μm and 2.00 μm, respectively. For EDFL, the mode-locked pulse centered at 1591.06 nm lasing wavelength was emitted with 3.19 nm spectral bandwidth and 1026 fs pulse width. Meanwhile, for THDFL, the generated pulse of 1410 fs was realized at 1951.60 nm central wavelength and 2.73 nm spectral bandwidth. The maximum average output power of 22.48 mW and 72.15 mW were measured from the EDFL and THDFL cavities, respectively. No perceptible variation of the optical spectrum and pulse width over one hour duration was observed for both laser cavities that indicated stable mode-locked pulse laser systems. These results demonstrate excellent performance from the nickel MOF-based SA and require further exploration of MOF-based SAs to enhance pulse mode-locking characteristics. [ABSTRACT FROM AUTHOR]

We utilize a femtosecond laser-inscribed small-period long-period fiber grating (SP-LPFG) to induce a nonlinear polarization rotation (NPR) effect for mode-locking pulses in a normal dispersion erbium-doped fiber laser (EDFL). The SP-LPFG has a length of 2.5 mm and a period of 25 μm. At wavelengths of 1556 nm and 1561 nm, it exhibits polarization-dependent loss (PDL) values of 20 dB and 14.5 dB, respectively, sufficient to trigger the NPR mechanism. With the pump power increased to 500 mW, the laser achieves normal dispersion mode-locked pulses centered at 1575 nm in the L-band, with a 3 dB bandwidth of 1.35 nm and a pulse width of 1.61 ps. The radio frequency (RF) spectrum reveals an signal-to-noise ratio (SNR) of up to 63.6 dB, demonstrating the excellent stability of the laser operation. This SP-LPFG holds promising applications, paving the way for efficient, compact, and stable normal dispersion ultrafast fiber lasers. [ABSTRACT FROM AUTHOR]

Dynamic control of the optical properties of gold nanostructures is crucial for advancing photonics technologies spanning optical signal processing, on-chip light sources and optical computing. Despite recent advances in tunable plasmons in gold nanostructures, most studies are limited to the linear or static regime, leaving the dynamic manipulation of nonlinear optical properties unexplored. This study demonstrates the voltage-controlled Kerr nonlinear optical response of gold nanofilms via the electrothermal effect. By applying relatively low voltages (~10 V), the nonlinear absorption coefficient and refractive index are reduced by 40.4% and 33.1%, respectively, due to the increased damping coefficient of gold nanofilm. Furthermore, a voltage-controlled all-fiber gold nanofilm saturable absorber is fabricated and used in mode-locked fiber lasers, enabling reversible wavelength-tuning and operation regimes switching (e.g., mode-locking—Q-switched mode-locking). These findings advance the understanding of electrically controlled nonlinear optical responses in gold nanofilms and offer a flexible approach for controlling fiber laser operations. Here the authors demonstrate voltage-controlled nonlinear optical response of gold nanofilm via electrothermal effect. They fabricate a voltage-controlled saturable absorber for achieving wavelength-tunability/operation-regime switching in a fiber laser. [ABSTRACT FROM AUTHOR]

The intrinsic non‐Hermiticity of photonic devices with tunable optical gain and loss makes them excellent platforms to explore and implement applications based on parity‐time symmetry, and a notable example is mode management in micro‐cavity lasers. Thus far, parity‐time‐symmetric lasers are fabricated via conventional top‐down etching processes, which are known to cause cavity sidewall roughness that is potentially detrimental to laser performance. Bottom‐up fabrication of parity‐time‐symmetric lasers, however, has seen limited success due to strict requirements on the uniformity of cavity morphology. Here, parity‐time‐symmetric lasing is demonstrated in coupled InP micro‐ring cavities grown directly by selective area epitaxy. With a facet engineering technique, ring laser cavities with a highly deterministic morphology are realized, enabling parity‐time‐symmetric laser designs. Furthermore, benefiting from the versatility and controllability of this bottom‐up process, lasing mode selectivity can be enhanced through coupling gap tuning and cavity shape engineering, leading to single‐mode lasing with a peak side mode suppression ratio exceeding 17 dB and a threefold single‐mode brightness enhancement compared to a single, uncoupled laser cavity. This work unlocks a lasing mode management strategy that is previously unavailable to bottom‐up laser cavities, which is a major step toward the realization of on‐chip, low‐loss, and single‐mode micro‐cavity lasers. [ABSTRACT FROM AUTHOR]

Optical frequency combs have revolutionized frequency metrology and spectroscopic measurements, enabling the most precise measurements of all physical quantities. However, precision frequency metrology heavily relies on mode‐locked laser combs, which are only directly available for a few selected near‐infrared wavelength ranges. Recently, a strong tendency emerged for combs in the mid‐infrared molecular fingerprint region. To this end, several methods for wavelength conversion have been proposed and demonstrated, which nevertheless cost a degradation of coherence properties. Here a first approach is presented toward measuring resulting phase noise fluctuations, exploiting the temporal resolution of the dispersive temporal interferometry (DTI) technique for experimentally unveiling the carrier‐envelope phase dynamics of a cw‐seeded femtosecond optical parametric amplifier (OPA). Particularly, it is experimentally demonstrated for the first time that unexpectedly low seed power levels suffice to exceed vacuum fluctuations by more than an order of magnitude, resulting in pulse‐to‐pulse phase fluctuations of 82 mrad at rather moderate cw seed levels of 8 mW. Additionally, a formula is provided that allows exact prediction of the experimentally observed noise levels. This study therefore provides new insight into the role of vacuum fluctuations in OPAs, which open up an avenue for coherent dual‐comb systems in the mid‐infrared and beyond. [ABSTRACT FROM AUTHOR]

In this paper, we demonstrate an ultrafast diamond Raman laser at 1240 nm with a pulse repetition rate of 956.62 MHz, a pulse duration of 39.5 ps, and an average power of up to 3.3 W based on synchronous pumping. The pump source is an electrical-pulse-modulated picosecond pulsed laser at 1064 nm with a repetition rate of 239.16 MHz and a pulse duration of 65.4 ps. A quadrupling repetition rate of the Raman pulse is achieved by synchronously amplifying both the forward and backward Raman pulses and the amplified Raman pulse undergoing two round trips in the resonator within one pump pulse period. The compression ratio of the pulse duration from the pump to the Raman is 1.66. This work offers a convenient and efficient method to significantly enhance the repetition rate of ultrafast crystalline Raman lasers and proves that a non-coherent ultrafast pump pulsed laser can be converted to a coherent mode-locked ultrafast Raman pulsed laser based on Raman conversion. [ABSTRACT FROM AUTHOR]

Fiber mode-locked lasers are nonlinear optical systems that provide ultrashort pulses at high repetition rates. However, adjusting the cavity parameters is often a challenging task due to the intrinsic multistability of a laser system. Depending on the adjustment of the cavity parameters, the optical output may vary significantly, including Q-switching, single and multipulse, and harmonic mode-locked regimes. In this study, we demonstrate an experimental implementation of the Soft Actor–Critic algorithm for generating a harmonic mode-locked regime inside a state-of-the-art fiber laser with an ion-gated nanotube saturable absorber. The algorithm employs nontrivial strategies to achieve a guaranteed harmonic mode-locked regime with the highest order by effectively managing the pumping power of a laser system and the nonlinear transmission of a nanotube absorber. Our results demonstrate a robust and feasible machine-learning–based approach toward an automatic system for adjusting nonlinear optical systems with the presence of multistability phenomena. [ABSTRACT FROM AUTHOR]

Passively harmonic mode-locking has been experimentally demonstrated in an erbium-doped fiber laser with large normal dispersion using single-multi-single mode structure as artificial saturable absorber. By increasing the pump power under the same polarization setting, the mode-locking operation can switch from fundamental mode-locked to 5th order harmonic mode-locked. Highest repetition rate of 4.26 MHz (5th order harmonic) is observed, with pulse width and pulse energy ascertained at 290 fs and 3.0 nJ, respectively. Excellent signal-to-noise ratio (SNR) of above 50 dB is observed for all harmonic orders. The findings validated that SMS structure can be used to generate stable and switchable high order of harmonic mode-locked. The low-cost SMS fiber for harmonic mode-locked generation technique could lay the groundwork for future sustainable industrial growth. [ABSTRACT FROM AUTHOR]

This study introduces a compact, portable femtosecond fibre laser system designed for synchronization with SPring‐8 synchrotron X‐ray pulses in a uniform filling mode. Unlike traditional titanium–sapphire mode‐locked lasers, which are fixed installations, our system utilizes fibre laser technology to provide a practical alternative for time‐resolved spectroscopy, striking a balance between usability, portability and cost‐efficiency. Comprehensive evaluations, including pulse characterization, timing jitter and frequency stability tests revealed a centre wavelength of 1600 nm, a pulse energy of 4.5 nJ, a pulse duration of 35 fs with a timing jitter of less than 9 ps, confirming the suitability of the system for time‐resolved spectroscopic studies. This development enhances the feasibility of experiments that combine synchrotron X‐rays and laser pulses, offering significant scientific contributions by enabling more flexible and diverse research applications. [ABSTRACT FROM AUTHOR]

This paper explores the production of linearly polarized laser output in a diode-pumped Yb:YAG laser at various pumping coupling ratios. To investigate the polarization mode locking mechanism with various pump coupling ratios, variations in beat frequency and beam profiles associated with different polarization states were analyzed. The study confirmed that the emission of linearly polarized laser with different mode-matching coefficients results from the coherent superposition of two orthogonally polarized eigenmodes within the resonator. Importantly, the experiment showed that adjusting pump coupling ratios allows achieving linearly polarized emission. Notably, within a specific range, linearly polarized laser emission remains unaffected by pumping coupling ratios. Beam quality factor measurements reveal that the beam quality of linearly polarized laser, generated through coherent superposition, surpasses that of partially polarized laser, with all beam quality factors being less than 1.5. [ABSTRACT FROM AUTHOR]

We demonstrate an all-polarization-maintaining (PM) ytterbium (Yb)-doped fiber laser with a figure-of-9 structure to generate mode-locked pulses with high single pulse energy and high repetition frequency. By exploiting the nonlinear amplifying loop mirror, a stably self-started mode-locking is achieved with a spectrum bandwidth of 13 nm and a pulse duration of 4.53 ps. The fundamental frequency is 97.966 MHz at the maximum output power of 143 mW in single pulse mode-locked operation, corresponding to the single pulse energy is 1.46 nJ. The output pulses maintain both high repetition frequency and high single-pulse energy. This laser oscillator can be an ideal seed source for applications such as high-energy amplifiers. [ABSTRACT FROM AUTHOR]

In recent years, 2D Cr2S3 has earned lots of attentions in the fields of photocatalysis and photodetector due to its outstanding environmental stability and high responsivity. However, up to now, the optical properties of 2D Cr2S3, especially the NLO properties of Cr2S3 have been rarely studied. In this work, the NLO properties of Cr2S3-nanoparticles in 1 μm have been investigated by using open-aperture (OA) Z-scan method. The nonlinear absorption coefficient (β), modulation depth and saturable intensity are measured to be -2.6 cm/GW, 11.5%, and 0.115 MW/cm2, respectively. Furthermore, by depositing Cr2S3 nanoparticles on a side-polished fiber and inserting into a ytterbium-doped fiber laser (YDFL) cavity, stable mode-locking laser and Q-switching laser with a pulse width of 10.2 ns and 2.95 µs are achieved, respectively. These results demonstrate that Cr2S3 is a promising saturable absorber (SA) for the fiber laser applications. [ABSTRACT FROM AUTHOR]

In this research work, the nonlinear Landau–Ginzburg–Higgs model under investigation on the base of auxiliary equation method. The nonlinear Landau–Ginzburg–Higgs equation mainly describe nonlinear wave propagation, categorizes wave velocity, and materializes several phenomena through the dispersive system. The secured optical soliton solutions are interested, more general and some novel in kink solitons, bright solitons, periodic singular solitons, anti-kink solitons and dark solitons. The physical structure of some explored solitons solutions are represented graphically as contour, 2D and 3D plots by utilizing the symbolic computational tool Mathematica. The secured soliton will be play important role to the investigation of nonlinear phenomena in the various domains of nonlinear sciences and engineering such as optical fibers, nonlinear dynamics, communication system, solitons wave theory, nonlinear optics, transmission system, electronic engineering and ocean engineering. The auxiliary equation method is a basic analytical, powerful, efficient approach for the investigation of optical soliton inside the nonlinear Landau–Ginzburg–Higgs equation and also other nonlinear equations. [ABSTRACT FROM AUTHOR]

Optoelectronic oscillators (OEOs), which have attracted extensive studies in the past decades, are high quality-factor optoelectronic feedback loops for generating various ultra-pure microwave signals. In essence, OEOs are also dissipative nonlinear systems with multiple timescale characteristics and abundant nonlinearities, which open the possibilities for exploring localized dissipative solitary waves. In this paper, we demonstrate a new-class temporal dissipative soliton, i.e., dissipative microwave photonic soliton molecule (DMPSM), in a dual-bandpass OEO. Both the numerical simulation and experiment are conducted to reveal the physical mechanism of DMPSM generation and to evaluate the characteristics of the generated DMPSM sequences. Unlike optical soliton molecules in mode-locked lasers, the formation of DMPSMs arises from the combined action of multiple timescale coupling, nonlinear bistability, and time-delayed feedback in the OEO cavity, where the soliton interval and number in a DMPSM can be well-controlled through varying the multiple timescale variables in the OEO cavity, and the repetition frequency of the DMPSMs can be tuned through changing that of the initially injected perturbation signal. Meanwhile, the generated DMPSM sequence performs with high stability and excellent coherence, which shows enormous application potentials in pulse radar detection, dense microwave comb generation, and neuromorphology. [ABSTRACT FROM AUTHOR]

On-chip generation of optical frequency combs using nonlinear ring resonators has enabled numerous applications of combs that were otherwise limited to mode-locked lasers. Nevertheless, on-chip frequency combs have relied predominantly on single-ring resonators. In this study, we experimentally demonstrate the generation of a novel class of frequency combs, the topological frequency combs, in a two-dimensional lattice of hundreds of ring resonators that hosts fabrication-robust topological edge states with linear dispersion. By pumping these edge states, we demonstrate the generation of a nested frequency comb that shows oscillation of multiple edge state resonances across ≈40 longitudinal modes and is spatially confined at the lattice edge. Our results provide an opportunity to explore the interplay between topological physics and nonlinear frequency comb generation in a commercially available nanophotonic platform. [ABSTRACT FROM AUTHOR]

Laser-based light detection and ranging (LIDAR) offers a powerful tool to real-timely map spatial information with exceptional accuracy and owns various applications ranging from industrial manufacturing, and remote sensing, to airborne and in-vehicle missions. Over the past two decades, the rapid advancements of optical frequency combs have ushered in a new era for LIDAR, promoting measurement precision to quantum noise limited level. For comb LIDAR systems, to further improve the comprehensive performances and reconcile inherent conflicts between speed, accuracy, and ambiguity range, innovative demodulation strategies become crucial. Here we report a dispersive Fourier transform (DFT) based LIDAR method utilizing phase-locked Vernier dual soliton laser combs. We demonstrate that after in-line pulse stretching, the delay of the flying pulses can be identified via the DFT-based spectral interferometry instead of temporal interferometry or pulse reconstruction. This enables absolute distance measurements with precision starting from 262 nm in single shot, to 2.8 nm after averaging 1.5 ms, in a non-ambiguity range over 1.7 km. Furthermore, our DFT-based LIDAR method distinctly demonstrates an ability to completely eliminate dead zones. Such an integration of frequency-resolved ultrafast analysis and dual-comb ranging technology may pave a way for the design of future LIDAR systems. Here the authors develop a dispersive Fourier transform (DFT) based LIDAR method utilizing phase-locked Vernier dual soliton laser combs and demonstrate improved precision in the measurements. [ABSTRACT FROM AUTHOR]

The use of femtosecond laser radiation pulses is a very important tool used for metals or cell ablation, structural changes of materials optical properties and many other applications. In this light, we investigate on the generation of continuous-waves solitary structures induced by the dynamics of laser radiation propagation in transparent media with passively mode-locked saturable absober. Thus, understanding the characteristic properties of the dynamics of laser radiations turns out to be a pertinent and important step towards the optimization of their uses, as well as enhancement of tecnology. Our model is characterized by a complex Ginzburg–Landau (CGL) equation with a strong nonlinearity. In full nonlinear regime, numerical simulations of the nonlinear equation revealed multi-periodic wave structures which turn out to be multi-pulse trains. When the number of photon K increases, an increase of the Saturation Power influences considerably the pulse train. The results clearly prove the existence of multi-pulse structures and bound-state solitons with strong nonlinearity on-like cubic-quintic and saturable nonlinearities. [ABSTRACT FROM AUTHOR]

Lasers of low-coherence have attracted the attention of researches since the first publications on this topic in the 1960s and up to the present time. Low-coherent quasi-continuous LD-pumped Nd:YVO4 and Nd:YAG lasers with ≈ 1 ms pulses of 1064 nm radiation at 10 Hz repetition rate and 21–47 W output power are reported. Spatial coherence of laser radiation was determined by the contrast C of speckle patterns, C = 0.02 - 0.1. These Nd-lasers optical efficiency is in the range 20%–50% (depending on the coherence level). The low coherence was obtained at multimode lasing in a plano-spherical resonator near its stability limit. Experimental data are commented on using the calculated dependences of the number of laser modes and the degree of coherence on resonator configurations and pump spot sizes. The achieved contrast values C < 0.03 are below the level of human perception and correspond to the level of spatial coherence typical for thermal sources of radiation. Possible applications of the developed low-coherent multimode Nd-lasers and directions for further research are discussed. [ABSTRACT FROM AUTHOR]

Ultrafast pulsed lasers are pivotal in advanced domains such as optical communications, optical metrology, all-optical sampling, optical frequency combs, laser ranging, and laser machining, where saturable absorbers (SAs) are crucial components. Various SAs based on two-dimensional (2D) materials have attracted great attention in recent years due to their low cost, high stability, large modulation depth, broadband absorption, and excellent optical nonlinearity. In this work, Bi2O2Te nanosheets (NSs) based SA with a saturation intensity of 20.6 MW/cm2 and a modulation depth of 2.2% was prepared by utilizing liquid phase exfoliation (LPE) technique, which was firstly applied to a passively mode-locked ytterbium-doped fiber laser (YDFL). The experiment results show that a sequence of dissipative soliton (DS) pulse train with a repetition frequency of 3.303 MHz was obtained at 1032.5 nm. The pulse duration, signal-to-noise ratio (SNR), and maximum peak power were 166 fs, 70 dB, 21 kW, respectively. The results not only underscore the potential of Bi2O2Te NSs-based SA for ultrafast photonics applications around 1 μm wavelength, but also open a way for further exploration of high-performance, all-fiber laser sources utilizing 2D materials. [ABSTRACT FROM AUTHOR]

Measurement device independent quantum key distribution (MDI QKD) has attracted growing attention for its immunity to attacks at the measurement unit, but its unique structure limits the secret key rate. Utilizing the wavelength division multiplexing (WDM) technique and reducing error rates are effective strategies for enhancing the secret key rate. Reducing error rates often requires active feedback control of wavelengths using precise external references. However, for a multiwavelength laser, employing multiple references to stabilize each wavelength output places stringent demands on these references and significantly increases system complexity. Here, we demonstrate a stable, wavelength-tunable multiwavelength laser with an output wavelength ranging from 1270 to 1610 nm. Through precise temperature control and stable drive current, we passively lock the laser wavelength, achieving remarkable wavelength stability. This significantly reduce the error rate, leading to an almost doubling of the secret key rate compared to previous experiments. Furthermore, the exceptional wavelength stability offered by our multiwavelength laser, combined with the WDM technique, has further boosted the secret key rate of MDI QKD. With a wide wavelength tuning range of 5.1 nm, our multiwavelength laser facilitates flexible operation across multiple dense wavelength division multiplexing channels. Coupled with high wavelength stability and multiple wavelength outputs simultaneously, this laser offers a promising solution for a high-rate MDI QKD system. [ABSTRACT FROM AUTHOR]

Soliton "molecules", i.e., bound states of two or several solitons, represent a fundamental concept, which manifests itself in various nonlinear systems. They are dynamically similar to chemical molecules, attracting great interest to fundamental studies and offering potential applications (such as multilevel encoding of optical data). Here, the study demonstrates a novel dichromatic soliton‐molecule compounds (DSMC) built as a hybrid bound state of multiple bound soliton pulses carried by two wavelengths in a fiber laser. The DSMCs are maintained by two different binding mechanisms, viz., the self‐phase modulation (SPM) interaction between temporal solitons at the same wavelength, mediated by their tails, and the cross‐phase modulation (XPM) interaction between solitons at different wavelengths. They also exhibit unique temporal and spectral vibration profiles. Both static DSMCs and ones with robust internal vibrations are generated experimentally in the fiber laser, and numerically as solutions of the corresponding dissipative nonlinear model. The findings reported here expand the concept of soliton molecules and further promote their similarity to chemical molecules. [ABSTRACT FROM AUTHOR]

The peculiar nonlinear optical responses of two-dimensional (2D) materials endow them highly attractive for photonics applications. This review systematically discusses the performance of pulsed lasers employing 2D materials as their modulation device. First, it is crucial to categorize 2D materials that can act as saturable absorbers, encompassing a range of substances such as Graphene, Black Phosphorus, Topological Insulators, MXene, and even heterojunction. Furthermore, a thorough investigation is conducted to analyze the performance indexes to study the nonlinear characteristics of 2D materials in the pulse generation. Especially, the focus is on the 1.5 μ m band ultrafast lasers utilizing 2D materials. This paper also provides a comprehensive analysis of the obstacles and prospects in 2D materials preparation, and their utilization in the pulse laser systems. [ABSTRACT FROM AUTHOR]