Soliton Rain Research Articles

Real-time characterizations of soliton explosions and pulsations in a Tm-doped fiber laser

Over the years, 2 μm mode-locked fiber laser has been widely developed as an important light source for various significant applications. Worth to note that, with the help of real-time spectroscopy technique, i.e., time-stretched dispersive Fourier transformation (TS-DFT), various complex nonlinear soliton dynamics have been revealed, such as soliton molecules, soliton explosions and soliton pulsations, enhancing our understanding of the ultrafast physics. However, due to the lack of appropriate dispersive components at 2 μm band with low optical transmission loss for TS-DFT measurement, the investigation of ultrafast soliton dynamical phenomena in the 2 μm mode-locked fiber lasers is still limited. In this work, we demonstrate the direct real-time observation of soliton explosion and pulsation phenomena at 2 μm band mode-locked fiber laser, for the first time as far as we know, by using specially designed linearly chirped fiber Bragg gratings as dispersive component for TS-DFT measurement. For explosions, we observe slight explosion and drastic explosion, respectively. Particularly, the soliton pulsating explosions are also characterized in real time where the explosions occur in the process of soliton pulsation. In addition, dual-wavelength soliton rains are also observed by carefully adjusting the cavity parameters. Our work provides supplements to the current investigation of 2 μm band ultrafast science, and might enrich our understanding of soliton dynamics.

Germanene Nanosheets as Saturable Absorbers for Soliton Rains and Large-Energy Pulse Generation in Passively Mode-Locked Fiber Lasers

Germanene Nanosheets as Saturable Absorbers for Soliton Rains and Large-Energy Pulse Generation in Passively Mode-Locked Fiber Lasers

Dual-comb soliton rains based on polarization multiplexing in a single-walled carbon nanotube mode-locked Er-doped fiber laser

Dual-comb soliton rains based on polarization multiplexing in a single-walled carbon nanotube mode-locked Er-doped fiber laser

Heterostructure nanocluster MOF-derived Ag-CuO: An emerging material for harmonic soliton pulses generation

In recent years, metal-organic framework (MOF) and their derivatives have attracted many researchers due to excellent characteristics, such as good stability, high capacity, and a modest third order nonlinear optical response. Compared with conventional optical materials, MOF-oxide are easier to benefit photonic research. However, for nonlinear optics and ultrafast photonics, research on MOFs-Transition metal oxide is still in its infancy. In this work, MOF-derived Ag-CuO was prepared by hydrothermal method and applied in passively mode-locked fiber laser. Experimental results show that MOF-derived Ag-CuO possesses excellent optical absorption, functioning as a saturable absorber (SA). The laser based on MOF-derived Ag-CuO SA realizes three different mode-locking states, including traditional soliton with the pulse width of 1.04 ps, 32nd order harmonic soliton molecule, and soliton rain pulse, with the signal-to-noise ratio (SNR) of 73 dB. This work lays the foundation of its application in ultrashort photonics and optical communication, broadening the future of MOF-derived Ag-CuO.

Soliton rain in all-polarization-maintaining mode locked fiber laser.

For the first time the phenomenon of soliton rain is observed in a mode-locked fiber laser with all-polarization-maintaining (all-PM) architecture. The laser is mode-locked using a semiconductor saturable absorber mirror (SESAM) and operates in the all-normal dispersion (ANDi) regime. The operation state of the laser can be switched from dissipative soliton to soliton rain by simply raising the pump power, without any manipulation of the intracavity polarization state given that all components of the resonator are made of PM fibers. The soliton rain generated in the laser is self-starting and replicable, since it occurs in every individual operation of the laser as the pump power is increased to an approximately invariant value.

Uni-and bidirectional soliton rains in a NALM mode-locked Tm-doped fiber laser

We report the generation of different drifting patterns of soliton rains in a Tm-doped fiber laser mode locked by the technique of nonlinear amplifying loop mirror. The directional control of drifting soliton rain has been achieved by varying pump power and polarization. At a stable pumping level, a kind of bidirectional soliton rain is observed from a unidirectional one for the first time. In the bidirectional case, the forward and backward solitons, leaving from the two sides of the condensed phase, appear in the spectrum as two typical soliton peaks on a wide pedestal, 2 nm in separation. The spectral result implies that the secondary drifting solitons are formed by developing one strong sideband of the primary soliton rain, induced by a shift of the transmission peak.

Multi-pulse dynamic patterns in a mode-locked erbium-doped fiber laser based on an Sb2S3-PVA saturable absorber

Multi-pulse dynamic patterns have been experimentally documented in a passively mode-locked (PML) erbium-doped fiber (EDF) laser using an Sb2S3-PVA saturable absorber (SA). The fundamental mode-locking operation, with a repetition rate of ∼3.22 MHz, a pulse width of ∼2.5 ps, a signal-to-noise ratio (SNR) of ∼50 dB and a peak power over 200 W, was achieved under a pump power from 280 to 360 mW with appropriate polarization states introduced by the polarization controllers (PCs). By rotating the orientation of the intra-cavity PCs carefully and slowly at a pump power of 350 mW, it was found that a multi-pulse bunch was transformed gradually from a single-pulse to a twelve-pulse bunch, with several intermediate transition states of multi-pulse bunches being observed. In addition, other characteristic modes including disordered multi-pulses and soliton rains have been experimentally observed by meticulously adjusting the polarization states of PCs at a pump power of 350 mW. Our systematic study clearly demonstrates that Sb2S3 has potential as an effective SA for generating different operation states of multi-pulses in PML anomalous-dispersion EDF lasers.

Generation of dissipative soliton resonance and soliton rain in passively mode-locked fiber laser based on GeTe saturable absorber

We report the generation of dissipative soliton resonance and soliton rain in an Er-doped fiber laser based on GeTe as saturable absorber. When the pump power is 60 mW, the fiber laser achieved the stable dissipative soliton resonance mode-locked operation. The pulse width of the trapezoidal envelope pulses increases from 21 to 35.5 ns with the increase of the pump power, while keeping the pulse profile and intensity invariable. By properly adjusting the polarization controller, a stable soliton rain pulse is obtained at the pump power of 70.4 mW. With the increase of pump power, its average output power increased from 0.52 to 1.56 mW, and its corresponding fundamental repetition rate, central wavelength and 3-dB bandwidth is 3.21 MHz, 1562.6 nm and 2.74 nm, respectively. The experimental results demonstrate that GeTe nanosheets could be developed as an effective saturable absorber for ultrashort pulse fiber lasers.

Soliton rains with isolated solitons induced by acoustic waves in a nonlinear multimodal interference-based fiber laser

We experimentally and theoretically demonstrate soliton rains with isolated solitons and soliton bunches in a passively mode-locked fiber laser, using a mode-locker based on a nonlinear multimodal interference technique. The isolated solitons are captured at the moments of integer multiples of 21 ns and 33 ns, which correspond to the acoustic modes in TR2m and R0m branches. The theory of nonlinear fiber optics is used to characterize the mechanism of capturing isolated solitons. The modal delay induced by the multimode fiber gives a revealing insight into the loss of capacity to capture and transition from soliton rains to bunches. Our study introduces a new way to precisely control the behaviors of multi-solitons and provides a potential tool for understanding complex nonlinear dynamics.

Spatiotemporal vectorial solitons in nonlinear ultrafast dual-core fiber lasers

The processes of soliton generation and interference focus on the complex nonlinear soliton dynamics resembling matter particles. In order to further understand the dynamic process of solitons from a multidimensional perspective, here we report the vectorial solitons nature under two-sets pulse splitting in a single cavity induced by dual-core fiber assisted ultrafast fiber lasers. Owing to the weakly coupled cores in symmetrical dual core fiber (SDCF), two pulse groups interaction are formed in a cavity. By using the dispersive Fourier transformation technique (DFT), it was found that the four-component polarized rotation vector solitons (PRVS) generate. Moreover, gradually increasing the power can obtain the locked soliton bound state in two core space, and the corresponding evolution is similar to that of non-degenerate bright solitons in Bose Einstein condensates (BEC). In addition, by properly controlling the soliton phase offset in SDCF, the soliton rain state of multi pulse evolution can be obtained. The related experimental results would be fruitful to the communities interested in soliton dynamics and frequency comb lasers.

Polarization attractors driven by vector soliton rain.

Soliton rain is a bunch of small soliton pulses slowly drifting near the main pulse having the period of a round trip. For Er-doped fiber laser mode-locked by carbon nanotubes, for the first time, we demonstrate both experimentally and theoretically a new type of polarization attractors controllable by vector soliton rain. With adjusting the pump power, vector soliton rain takes the form of pulses with rotating states of polarization which enable transforming slowly evolving trajectories on the Poincaré sphere from the double-scroll spiral to the circle. The obtained results on controlling complex multisoliton dynamics can be of interest in laser physics and engineering with potential applications in spectroscopy, metrology, and biomedical diagnostics.

TMO‐Derived γ‐MnO2 Nanosheets for Harmonic Soliton Molecule Pulses Generation

AbstractThe interaction of 2D materials with ultrashort laser excitation generates fiber soliton pulses with extreme nonlinear absorption characteristics, which are essential for generating ultrafast pulses. However, searching for suitable nanomaterials to achieve versatile photonic properties is difficult. Factors such as cost, manufacturing process complexity, optical response time, and nonlinear absorption effects make the balance between high performance and low cost a constant challenge, greatly hindering the research and development of ultrafast photonics technology. For fiber soliton pulse systems, γ‐MnO2, as a transition metal oxide (TMO), shows excellent potential among many candidate nanomaterials due to its rich narrow‐band optoelectronic microstructural features and nonlinear optical properties. In this work, this fundamental trade‐off is overcome and γ‐MnO2 is investigated as a nonlinear optical material for multifunctional fiber soliton pulsed lasers. The outputs of conventional soliton pulses, 23rd order harmonic soliton‐molecule picosecond pulses, continuous and soliton pulse waves coexist in dual‐wavelength, and soliton rain pulses are obtained simultaneously, successfully achieving a technological breakthrough in nanophotonics and pulse dynamics. It is demonstrated that MnO2 has a broad application prospect for generating nonlinear effects such as fiber optic soliton pulses, which provides an effective and rich theoretical support for developing ultrafast photonics of narrow‐band optoelectronic materials.

Passively mode-locked Ho-doped fiber laser with soliton rain and noise-like pulse regime

A passively Ho-doped fiber laser at 2 μm with soliton rain and noise-like pulse (NLP) operation regime has been realized by using nonlinear polarization rotation (NPR) technology. By adjusting the polarization state, the evolution phenomenon of soliton rain pulse and the NLP are obtained. The typical NLP mode-locking operation regime is achieved by finely adjusting pump power and polarization state, which delivers a corresponding pulse energy of 8.93 nJ with pulse width of 1.31 ps. The soliton rain operation regime with multiple solitons is achieved by finely adjusting pump power, which delivers a corresponding pulse energy of 22.98 nJ with pulse width of 1.21 ps. In addition, a NLP mode-locking operation regime is obtained again under a proper pump power and polarization state with a corresponding pulse energy of 34.14 nJ and pulse width of 1.18 ps. The experimental results well demonstrate the evolution of ultrashort pulse regime with the pump power and polarization state in passively mode-locked Ho-doped fiber lasers at 2 μm.

Passively Mode-Locked Ho-Doped Fiber Laser with Soliton Rain and Noise-Like Pulse Regime

Passively Mode-Locked Ho-Doped Fiber Laser with Soliton Rain and Noise-Like Pulse Regime

Nonlinearity managed passively harmonic mode-locked Er-doped fiber laser based on carbon nanotube film.

We examine the implication of intracavity nonlinearity for harmonic mode locking (HML) by exploiting highly nonlinear fiber in a carbon nanotube film mode-locked Er-doped fiber laser. It is found that the reasonably large nonlinearity is of benefit to increase the extent of harmonic order while the excessive nonlinearity leads to some peculiar multi-pulse patterns such as noise-like pulse and soliton rain. Via appropriate nonlinearity management, nearly 4 GHz repetition rate pulses at the 91st harmonic with 936 fs pulse duration are delivered under the pump power of 280 mW. The pulse stability is evidenced by the super-mode suppression ratio of 35.6 dB. To the best of our knowledge, it is the highest repetition rate yet reported for a passively HML fiber laser based on a film-type physical saturable absorber. Furthermore, the laser exhibits steep pumping efficiency slope of ${\gt}{19}\;{\rm MHz/mW}$, which is also a record among all of the passively HML fiber lasers.

Real-time observation of the Casimir-like interaction induced pulse dynamics in a fiber laser

We study soliton rain (SR) dynamics experimentally in a passively mode-locked fiber laser based on gold nanoparticles. The complex behavior of the SR, including cases where the speed of the deuterogenic solitons drift was faster than that of the condensed soliton phase (CSP), cases where the drift was slower, and even cases with deuterogenic solitons both faster and slower, have all been observed by adjusting only the cavity polarization controllers and the pump power. It is unveiled that the noise-mediated Casimir-like pulse interaction mechanism accounts for these dynamical patterns. Further, the real-time characteristics of the CSP were observed in detail utilizing the dispersion Fourier transform technique. The study showed that the intensity of the CSP spectrum was redistributed with the soliton drift, while the energy of the CSP spectrum was conserved. This study will provide a new perspective for the regimes of complex pulse dynamic behavior.

SnSe2 realizes soliton rain and harmonic soliton molecules in erbium-doped fiber lasers

Two-dimensional layered metal chalcogenides (LMCs) are widely used in battery anode materials, energy conversion, and semiconductor devices, because of their high energy storage characteristics, high thermoelectric characteristics, and large electron mobility. SnSe2 as a kind of LMC has strong nonlinear optical characteristics. However, its research on dissipative system dynamics as a saturable absorber has not been studied. In this work, we obtained SnSe2 nanosheets using lithium ion intercalation and we reported a passively mode-locked fiber laser with SnSe2 as a saturable absorber to achieve the dissipative soliton in a dissipative system. Due to the high third-order nonlinearity of SnSe2, the evolution of square wave pulses from 2 to 16 ns was obtained in a fiber ring cavity. Through adjusting the polarization state, the evolution phenomenon of soliton rain, the soliton rain phenomenon with a spectrum of dual-wavelengths, and a bound state harmonic phenomenon with a frequency of 313 MHz were obtained. Therefore, the strong nonlinear fiber laser based on SnSe2 provides a good platform for study the pulsation, explosion, rainfall and other phenomena.

Generation of noise-like pulses and soliton rains in a graphene mode-locked erbium-doped fiber ring laser

We demonstrate the generation of noise-like pulses (NLPs) and soliton rains in a graphene saturable absorber mode-locked erbium-doped fiber laser. Typical NLPs are obtained at a proper pump power and in a cavity polarization state. The soliton rain operation with multiple solitons can be achieved by finely adjusting the cavity polarization state. In addition, distinctive multi-soliton interactions are observed and investigated, including the fundamental mode-locking and multiple pulses. The experimental results can help further understand nonlinear pulse dynamics in ultrafast optics.

Corrections to “Evolution of Soliton Rain in a Tm-Doped Passive Mode-Locked All-Fiber Laser” [Aug 20 Art. no. 1503408

Presents corrections to the byline information for the above named paper.

570 MHz harmonic mode-locking in an all polarization-maintaining Ho-doped fiber laser.

In this paper, we demonstrate a 570.0 MHz harmonically mode-locked all-polarization-maintaining Ho-doped fiber laser based on semiconductor saturable absorbed mirror. Firstly, the laser operates in the 15.4 MHz fundamental mode-locked soliton regime, emitting 2051.5 nm, 1.62 ps soliton pulse without Kelly sidebands. And then, the stable 37th-order harmonic mode-locked soliton with maximum repetition rate up to 570.0 MHz at 2053nm is generated. Moreover, colorful soliton rain behaviors are also discussed.