Generation Of Dissipative Solitons Research Articles

Generation and evolution dynamics of gain-guided dissipative solitons in a Tm-doped fiber laser

The generation of dissipative solitons from a mode-locked fiber laser can enhance emission energy, while the insertion of a bandwidth filter exposes the system to complexity. This study presents the first generation and evolution dynamics of gain-guided dissipative solitons (GGDSs) in Tm-doped fiber lasers exploiting the finite gain bandwidth. The results highlight the intricate interplay of finite gain bandwidth with dispersion and nonlinearity in governing the dynamics of GGDSs. An increase in pump power significantly broadens the emission spectrum, which in turn introduces the finite gain bandwidth to the generation of GGDSs. Consequently, linear chirp accumulates, promoting high-energy ultrashort pulse generation after external compression. However, an increase in round-trip group delay dispersion leads to a narrower spectral bandwidth, which can weaken the influence of the finite gain bandwidth, resulting in decreased soliton energy and broader pulse duration. The investigation of GGDS evolution dynamics within the cavity also provides us with a deeper insight into the characteristics of GGDS. Overall, this research offers important guidance for designing high-performance Tm-doped fiber lasers with simple structures that fully exploit the finite gain bandwidth.

Continuous-wave driving elucidates the desynchronization dynamics of ultrashort dissipative Raman solitons generated in dispersive Kerr resonators.

Phase-coherent pulsed driving of passive optical fiber resonators enables the generation of ultrashort dissipative Raman solitons with durations well below 100 fs. The existence and characteristics of such solitons critically depend on the desynchronization between the pulsed driving source and the resonator round trip time, yet the full mechanism through which these dependencies arise remains unclear. Here, we numerically demonstrate that Raman solitons can exist even under conditions of continuous-wave (CW) driving, and by numerically examining the existence and characteristics of Raman solitons under such conditions, we elucidate the role of desynchronization in pulse-driven systems. In addition to providing new insights into the existence and characteristics of ultrashort Raman solitons, our analysis yields a qualitative explanation for the range of desynchronizations over which the solitons can exist.

Passively harmonic dissipative soliton generation in normal dispersion erbium-doped fiber laser using SMS fiber as artificial saturable absorber

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.

Repetition rate tuning and locking of solitons in a microrod resonator.

Recently, there has been significant interest in the generation of coherent temporal solitons in optical microresonators. In this Letter, we present a demonstration of dissipative Kerr soliton generation in a microrod resonator using an auxiliary-laser-assisted thermal response control method. In addition, we are able to control the repetition rate of the soliton over a range of 200 kHz while maintaining the pump laser frequency, by applying external stress tuning. Through the precise control of the PZT voltage, we achieve a stability level of 3.9 × 10-10 for residual fluctuation of the repetition rate when averaged 1 s. Our platform offers precise tuning and locking capabilities for the repetition frequency of coherent mode-locked combs in microresonators. This advancement holds great potential for applications in spectroscopy and precision measurements.

Analysis of generation of high-energy dissipative solitons in all-normal-dispersion mode-locked photonic crystal fiber laser

In this research, an all-normal-dispersion mode-locked photonic crystal fiber laser (MLPCFL) is simulated. Three types of large-pitch PCFs with a small value of self-phase modulation coefficient are introduced and their fundamental characteristics are numerically investigated. They are then employed in the laser cavity and the performance of MLPCFL using these three different large-pitch PCFs is compared. According to the simulation results, as the hole-to-hole distance gets larger, the pulse spectrum profile changes from M-shape to parabolic and the temporal width of the pulses is also increased. Additionally, the simulation demonstrates that the presented laser has the potential to generate pulses with an energy of 450 nJ, if a 5 m length of passive PCF with Ʌ= 20 µm (Ʌ is hole-to-hole distance) is incorporated into the laser cavity. The results reveal that, by inserting a 1 m-long Yb-doped PCF with Ʌ= 20 µm at the output port of the laser, it becomes possible to generate pulses with an energy of 45 μJ and a peak power of 2.47 MW. The chirped output pulses from the amplifier are compressed after passing through the dispersion delay line and resulting in a reduction of the FWHM to 150 fs.

Reversible generation of dissipative Kerr solitons in a microresonator by the backward tuning method

Reversible generation of dissipative Kerr solitons in a microresonator by the backward tuning method

Vliyanie nagreva na generatsiyu i svoystva platikonov v vysokodobrotnykh opticheskikh mikrorezonatorakh

Pumping a high-Q optical microresonator by an external laser is inevitably associated with thermal effects. They have a significant impact on the dynamics of nonlinear processes in such structures, including the generation of optical frequency combs and dissipative solitons. The generation process and the properties of bright solitons in such heated microresonators with anomalous group velocity dispersion (GVD) have been well studied, and a number of methods have been developed to minimize the effect of thermal processes. However, for dark solitons or platicons excited at normal GVD, these issues have been studied significantly less. In this work, the properties of platicons in heated microresonators are analyzed, and it is shown that in the case of “positive” thermal effects, when the direction of the thermal shift of the resonance frequencies of a microresonator coincides with the direction of the nonlinear shift, the widest high-energy platicons with the duration close to the round trip time in the resonator are stable. In the case of “negative” thermal effects, narrow low-energy platicons remain stable. Moreover, in microresonators with “negative” thermal effects, the interaction between cubic nonlinear and thermal processes can ensure the generation of platicons without special techniques required in other cases.

Cavity soliton formation in Kerr comb oscillators via input phase and amplitude modulation in the presence of high order dispersion

The generation of dissipative cavity solitons (CSs) in Kerr microresonators through pulsed driving is an effective method for generating coherent optical microcombs. Yet, the underlying physics has not been fully investigated. Our study investigates the effect of high-order dispersion on the generation of Kerr frequency combs in Si3N4 microresonator driven by phase- and amplitude-modulated inhomogeneities of the pump which had not been studied before. Here, we present a numerical and theoretical analysis of the effects of desynchronization and the pulsed driving chirp parameter on the train of solitons circulating in the cavity for various detunings. In this case, deterministic production of a K-band single soliton, as well single breather soliton has been investigated. Our results show that high-order dispersion can also affect CSs positioning, stability, and existence.

Research on wideband dissipative soliton generation and the dynamics process

Research on wideband dissipative soliton generation and the dynamics process

Ultrafast dissipative soliton generation in anomalous dispersion achieving high peak power beyond the limitation of cubic nonlinearity

The maximum peak power of ultrafast mode-locked lasers has been limited by cubic nonlinearity, which collapses the mode-locked pulses and consequently leads to noisy operation or satellite pulses. In this paper, we propose a concept to achieve mode-locked pulses with high peak power beyond the limitation of cubic nonlinearity with the help of dissipative resonance between quintic nonlinear phase shifts and anomalous group velocity dispersion. We first conducted a numerical study to investigate the existence of high peak power ultrafast dissipative solitons in a fiber cavity with anomalous group velocity dispersion (U-DSAD) and found four unique characteristics. We then built long cavity ultrafast thulium-doped fiber lasers and verified that the properties of the generated mode-locked pulses match well with the U-DSAD characteristics found in the numerical study. The best-performing laser generated a peak power of 330 kW and a maximum pulse energy of 80 nJ with a pulse duration of 249 fs at a repetition rate of 428 kHz. Such a high peak power exceeds that of any previous mode-locked pulses generated from a single-mode fiber laser without post-treatment. We anticipate that the means to overcome cubic nonlinearity presented in this paper can give insight in various optical fields dealing with nonlinearity to find solutions beyond the inherent limitations.

Dynamics of dissipative structures in coherently-driven Kerr cavities with a parabolic potential

By means of a modified Lugiato–Lefever equation model, we investigate the nonlinear dynamics of dissipative wave structures in coherently-driven Kerr cavities with a parabolic potential. This potential stabilizes the system dynamics, leading to the generation of robust dissipative solitons in the positive detuning regime, and of higher-order solitons in the negative detuning regime. In order to understand the underlying mechanisms which are responsible for these high-order states, we decompose the field on the basis of linear eigenmodes of the system. This permits to investigate the resulting nonlinear mode coupling processes. By increasing the external pumping, one observes the emergence of high-order breathers and chaoticons. Our modal content analysis reveals that breathers are dominated by modes of corresponding orders, while chaoticons exhibit proper chaotic dynamics. We characterize the evolution of dissipative structures by using bifurcation diagrams, and confirm their stability by combining linear stability analysis results with numerical simulations. Finally, we draw phase diagrams that summarize the complex dynamics landscape, obtained by varying the pump, the detuning, and the strength of the potential.

Raman dissipative soliton source of ultrashort pulses in NIR-III spectral window.

We present a novel fiber source of ultrashort pulses at the wavelength of 1660 nm based on the technique of external cavity Raman dissipative soliton generation. The output energy of the generated 30 ps chirped pulses is in the range of 0.5-3.6 nJ with a slope efficiency of 57%. Numerical simulations are in excellent agreement with the experimental results and the shape of the compressed pulses. The compressed pulses consist of a central part with a duration of 300 fs and a weak pedestal. Our results clearly demonstrate the potential to extend the spectral range of the Raman-assisted technique for generating ultra-short pulses to new frequency regions, including biomedical windows. This paves the way for the development of new dissipative soliton sources in these bands.

Nonlinear-Fourier-Transform-Based Dynamic Analyses on the Multiple Cavity Solitons in Kerr Microresonators

The Kerr microresonators have aroused widespread interests for their ultrahigh integration, compatible fabrication and ultralow energy consumption. Similar to the traditional mode-locked fiber lasers, the microresontors can sustain the generation of dissipative solitons called cavity solitons relying on the double balance of gain and loss as well as nonlinearity and dispersion. The state of multiple solitons is common in the microresonator with anomalous dispersion. In particular, an ideal state named as soliton crystals is obtained when the multiple solitons have a equidistant arrangement. And recent experiments have successfullly observed soliton crystals in the Kerr microresonators. To intuitively reveal the formation and evolution dynamics of the multiple solitons and get insight into the underlying physical mechanisms of soliton crystals, we applied the nonlinear Fourier transform to project these states into nonlinear discrete spectrum. The discrete spectra of single soliton with different modulated background waves have been displayed, which can help distinguish different optical components. Then, the nonlinear spectrum evolution of normal multiple solitons state shows the typical nonlinear states of the intracavity field. And the equidistant solitons have the effects of power enhancement, whose spectral intensity is several times that of a single soliton state. Comparing with the discrete spectrum of the equidistant solitons, the solitons inside the soliton crystals interact with each other by the modulated background. Our results suggest that the nonlinear Fourier transform is a powerful technique to characterize soliton dynamics in the Kerr microresonator, which provides a new perspective to understand the interactions of cavity solitons.

Generation of dissipative soliton in erbium-doped fiber laser passively mode locked by InSb saturable absorber

A stable dissipative soliton (DS) erbium-doped fiber (EDF) laser passively mode locked by InSb saturable absorber (SA) is achieved for the first time. The used InSb SA is prepared by magnetron-sputtering deposition (MSD) method based on tapered fiber. The achieved stable dissipative soliton (DSs) possess a central wavelength of 1570 nm, pulse duration of 25.14 ps, repetition rate of 14.91 MHz, and a maximum average output power of 11.57 mW, respectively. The experiment verifies the merits of high thermal damage resistance, superb long-term stability and excellent antioxidant capacity of the prepared InSb SA, as well enriches in-depth DSs researches based on 2D-material SAs.

Terahertz optical solitons from dispersion-compensated antenna-coupled planarized ring quantum cascade lasers.

Quantum cascade lasers (QCLs) constitute an intriguing opportunity for the generation of on-chip optical dissipative Kerr solitons (DKSs). Originally demonstrated in passive microresonators, DKSs were recently observed in mid-infrared ring QCL paving the way for their achievement even at longer wavelengths. To this end, we realized defect-free terahertz ring QCLs featuring anomalous dispersion leveraging on a technological platform based on waveguide planarization. A concentric coupled waveguide approach is implemented for dispersion compensation, while a passive broadband bullseye antenna improves the device power extraction and far field. Comb spectra featuring sech2 envelopes are presented for free-running operation. The presence of solitons is further supported by observing the highly hysteretic behavior, measuring the phase difference between the modes, and reconstructing the intensity time profile highlighting the presence of self-starting 12-picosecond-long pulses. These observations are in very good agreement with our numeric simulations based on a Complex Ginzburg-Landau Equation (CGLE).

Generation of dissipative Kerr solitons in a passive fiber Kerr resonator with a fast saturable absorber

The generation of dissipative Kerr solitons (DKSs) in a passive fiber Kerr resonator with a fast saturable absorber (SA) is studied numerically. Simulation results demonstrate the generation of DKSs in SA-based fiber Kerr resonators. The impact of the properties of an SA, including the modulation depth and the saturation power, on the performances of DKSs is studied. Our results show the existence of DKSs in SA-based passive fiber Kerr resonators, suggesting that the SA provides additional degrees of freedom to get access to the DKS regime in Kerr resonators in addition to the detuning and the pump. These findings provide guidance for the experimental realization of the generation of DKSs in SA-based fiber Kerr resonators.

Dispersion-less Kerr solitons in spectrally confined optical cavities

Solitons are self-reinforcing localized wave packets that manifest in the major areas of nonlinear science, from optics to biology and Bose–Einstein condensates. Recently, optically driven dissipative solitons have attracted great attention for the implementation of the chip-scale frequency combs that are decisive for communications, spectroscopy, neural computing, and quantum information processing. In the current understanding, the generation of temporal solitons involves the chromatic dispersion as a key enabling physical effect, acting either globally or locally on the cavity dynamics in a decisive way. Here, we report on a novel class of solitons, both theoretically and experimentally, which builds up in spectrally confined optical cavities when dispersion is practically absent, both globally and locally. Precisely, the interplay between the Kerr nonlinearity and spectral filtering results in an infinite hierarchy of eigenfunctions which, combined with optical gain, allow for the generation of stable dispersion-less dissipative solitons in a previously unexplored regime. When the filter order tends to infinity, we find an unexpected link between dissipative and conservative solitons, in the form of Nyquist-pulse-like solitons endowed with an ultra-flat spectrum. In contrast to the conventional dispersion-enabled nonlinear Schrödinger solitons, these dispersion-less Nyquist solitons build on a fully confined spectrum and their energy scaling is not constrained by the pulse duration. Dispersion-less soliton molecules and their deterministic transitioning to single solitons are also evidenced. These findings broaden the fundamental scope of the dissipative soliton paradigm and open new avenues for generating soliton pulses and frequency combs endowed with unprecedented temporal and spectral features.

Demonstration of multiple dissipative solitons with nickel-based metal organic framework saturable absorber

In this work, we have demonstrated the generation of dissipative soliton from single to multi-pulsing phenomenon. The generation of ultrashort pulses was achieved with nickel-based metal organic framework (Ni-MOF) as saturable absorber in a ring cavity erbium-doped fiber laser. The SA was fabricated by spin-coating Ni-MOF/polydimethylsiloxane composite on a tapered fiber substrate, which had an insertion loss of 2.82 dB, a modulation depth of 4.61 %, and saturation intensity of 30.12 MW/cm2. A self-started DS mode-locked pulse was observed at 1559.89 nm central wavelength with 3-dB bandwidth of 19.72 nm at threshold pump power of 33.5 mW. Its pulse width of 7.89 ps was recorded at 7.94 MHz repetition rate. The nature of pulse splitting was observed up to three pulses which were separated with 2.62 ns time spacing with the increment of pump power until 134.2 mW. The generated multiple dissipative soliton pulses realized in the laser cavity through Ni-MOF saturable absorber were stable and invariant for 1-hour stability measurement.

GaSb Film is a Saturable Absorber for Dissipative Soliton Generation in a Fiber Laser

Nanotechnology is at the forefront of scientific research and offers great prospects for the development of technology. As a type of III-V semiconductor, GaSb materials exhibit numerous outstanding optical and electrical characteristics that are very promising for nonlinear optical device applications. In this study, the electronic band structures of GaSb are theoretically calculated, and its application in dissipative soliton fiber lasers is validated. A GaSb thin film is deposited on a microfiber using magnetron sputtering deposition, and the morphology, chemical composition, structure, and nonlinear optical characteristics of the proposed microfiber-GaSb device are investigated. After incorporating it into an Er-doped fiber laser, dissipative soliton laser pulses are readily obtained with a fundamental frequency of 43.5 MHz. With increasing pump power, the fiber laser could work in the fundamental frequency mode-locking state. At a pump power of 570 mW, the pulse width and the output power are measured to be 917 fs and 49.75 mW, separately. These results reveal that GaSb can be used as an efficient saturable absorber, which will have potential applications in ultrafast optics.

Integrated buried heaters for efficient spectral control of air-clad microresonator frequency combs

Integrated heaters are essential in the photonics toolbox, particularly for microresonator frequency tuning through the thermo-refractive effect. Resonators that are fully embedded in a solid cladding (typically SiO2) allow for straightforward lossless integration of heater elements. However, air-clad resonators, which are of great interest for short wavelength dispersion engineering and direct interfacing with atomic/molecular systems, do not usually have similar low loss and efficient heater integration through standard fabrication. Here, we develop a new approach in which the integrated heater is embedded in SiO2 below the waveguiding layer, enabling more efficient heating and more arbitrary routing of the heater traces than possible in a lateral configuration. We incorporate these buried heaters within a stoichiometric Si3N4 process flow that includes high-temperature (>1000 °C) annealing. Microring resonators with a 1 THz free spectral range and quality factors near 106 are demonstrated, and the resonant modes are tuned by nearly 1.5 THz, a 5× improvement compared to equivalent devices with lateral heaters. Finally, we demonstrate broadband dissipative Kerr soliton generation in this platform and show how the heaters can be utilized to aid in bringing relevant lock frequencies within a detectable range.