Dissipative Soliton Resonance Research Articles

Period doubling and merging of multiple dissipative-soliton-resonance pulses in a fiber laser.

Period doubling (PD) and the merging of multiple dissipative-soliton-resonance (DSR) pulses are investigated in a fiber laser. Depending on the initial conditions and operation settings, various PDs of multiple DSR pulses are achieved. For two coexisting DSR pulses, we observe PD on both pulses or PD on a single pulse while the other pulse maintains period one. For three coexisting DSR pulses, PD on all pulses or PD on one/two pulse(s) are achieved when the other pulses maintain period one. It is observed that excessively increasing the pump power could destroy the PD behavior. Within certain parameters, PD behavior can be maintained by increasing the pump power. Apart from the appearance of PD, it is found that two DSR pulses may merge into a single DSR pulse if the pulse interval is small enough during pump power increase.

Generation of dissipative soliton resonance in a fiber laser based on a nonlinear optical loop mirror

We experimentally demonstrate generation of mode-locked pulses in dissipative soliton resonance (DSR) regime. The DSR pulses are obtained from a passively mode-locked figure-8 Er:Yb doped fiber laser operating in large net anomalous dispersion regime. The modelocked laser emission is based on a polarization-imbalanced nonlinear optical loop mirror (NOLM), acting as artificial saturable absorber. Stable square DSR pulses, obtained by carefully adjusting the NOLM properties, increase their duration from 2.47 ns to 46.52 ns as the pump power is increased from 0.68 to 6.31 W. With the maximum pump power launched, average output power of 73.95 mW with pulse energy of 53.39 nJ is achieved.

1.3\xa0\xb5m dissipative soliton resonance generation in Bismuth doped fiber laser

In this work, a Figure-9 (F9) bismuth-doped fiber laser (BiDFL) operating in the dissipative soliton resonance (DSR) regime is presented. The 1338 nm laser used a BiDF as the active gain medium, while a nonlinear amplifying loop mirror (NALM) in an F9 configuration was employed to obtain high energy mode-locked pulses. The wave breaking-free rectangular pulse widened significantly in the time domain with the increase of the pump power while maintaining an almost constant peak power of 0.6 W. At the maximum pump power, the mode-locked laser delivered a rectangular-shaped pulse with a duration of 48 ns, repetition rate of 362 kHz and a radio-frequency signal-to-noise ratio of more than 60 dB. The maximum output power was recorded at around 11 mW with a corresponding pulse energy of 30 nJ. This is, to the best of the author’s knowledge, the highest mode-locked pulse energy obtained at 1.3 μm as well as the demonstration of an NALM BiDFL in a F9 configuration.

Tunable peak power square-wave pulse based on an all-PM thulium-doped mode-locked fiber laser.

Nanosecond dissipative soliton resonance pulse is a demonstration of an all polarization-maintaining (PM) thulium-doped fiber laser in a nonlinear amplifying loop mirror (NALM)-based figure-eight configuration. Each loop of the apparatus includes a controllable power amplifier. With increased amplifier power, pulse width broadens linearly from 3.6 to 13.5 ns, and maximum single pulse energy can reach 27.5 nJ. Interestingly, the output peak power presents two completely opposite proportional effects in terms of the variation of settings for two amplifiers, respectively. The experimental results show that the NALM loop plays an important role for tunable pulse duration, and the unidirectional ring part makes a significant contribution for power scaling.

Coherence characterization of nanosecond rectangular pulses in passively mode-locked fiber lasers

Dissipative soliton resonance (DSR) phenomenon is a recent concept of pulse formation proposed to achieve a high-energy passively mode-locked fiber laser. Such pulses have general features, e.g., flat-top temporal profile, energy scalability, and temporal coherence. To identify the nature of various rectangular pulses which share most of DSR features, it is important to verify their coherence. When a pulse is in the nanosecond range, the experimental study of the coherence is a complex task, which is overlooked in the literature. In this work, a novel approach is proposed for the first time to study the coherence of nanosecond rectangular pulses. It is based on two different methods: Mach-Zehnder interferometer (MZI) and dispersive Fourier transformation (DFT).

Sub-nanosecond gain-switched Ytterbium-doped fiber laser pumped by 1030 nm dissipative soliton resonance mode-locked fiber laser

In this work we report on a tandem pumped gain-switched Yb-doped fiber laser. We used an amplified dissipative soliton resonance mode-locked fiber laser with the wavelength of 1030 nm as a source of high repetition rate pulsed pump, incorporated with a CW diode laser at the wavelength of 976 nm in hybrid pump scheme. Sub-nanosecond narrow line-width gain-switched pulses with peak power of 10 kW at 1064 nm have been achieved. The line-width of the gain-switched laser is less than 0.06 nm and the repetition rate is 683 kHz.

Switchable dissipative soliton resonance and noise like pulses regimes in a mode-locked double-clad thulium doped fiber laser

We report an experimental study of switchable rectangular pulses generation in a passively mode-locked double-clad thulium-doped fiber laser operating in the anomalous dispersion regime. A fiber loop mirror and a polarization imbalanced nonlinear optical loop mirror (NOLM) forms the linear cavity. The loop in the NOLM includes a quarter-wave retarder, which allows switching between two regimes of rectangular pulse generation. The laser generates rectangular noise-like pulses (NLPs) or dissipative soliton resonance (DSR) pulses with 1.18 MHz repetition rate at ∼1990 nm. At the maximum pump power of 10 W, rectangular pulses with energy of up to 540 nJ in DSR operation and 482 nJ in NLP operation were obtained with output average power of 640 mW and 571 mW, respectively.

Generation of multi-wavelength square pulses in the dissipative soliton resonance regime by a Yb-doped fiber laser* *Project supported by the National Natural Science Foundation of China (Grant No. 41875040), the Natural Science Foundation of Anhui Province, China (Grant No. 2008085MF211), the Foundation for Young Talents in College of Anhui Province (Grant No. gxyqZD2019034), and the Key Natural Science Research Project

Multi-wavelength square pulses are generated in the dissipative soliton resonance (DSR) regime by a Yb-doped fiber laser (YDFL) with a long cavity configuration. The spectral filter effect provided by a passive fiber with low-stress birefringence facilitates the establishment of multi-wavelength operation. Through appropriate control of the cavity parameters, a multi-wavelength DSR pulse can be generated in single- and dual-waveband regions. When the multi-wavelength DSR works in the 1038 nm waveband, the pulse duration can broaden from 2 ns to 37.7 ns. The maximum intra-cavity pulse energy is 152.7 nJ. When the DSR works in the 1038 nm and 1080 nm wavebands, the pulse duration can be tuned from 2.3 ns to 10.5 ns with rising pump power. The emergence of the 1080 nm waveband is attributed to the stimulated Raman scattering (SRS) effect. Our work might help a deeper insight to be gained into DSR pulses in all-normal-dispersion YDFLs.

Influence of reverse saturable absorption effect on conventional and dissipative solitons fiber lasers

We numerically investigate the influence of the reverse saturable absorption effect of real saturable absorbers on conventional and dissipative solitons. The results show that the reverse saturable absorption effect leads to more loss and clamps peak power of both conventional and dissipative solitons, but plays different roles on their properties. When the cavity operates at conventional solitons state, the reverse saturable absorption effect restricts the maximum pulse energy to less than 0.1 nJ, facilitates the formation of multiple solitons, but maintains the time-bandwidth product close to 0.315, indicating the pulses maintain the sech2 shape. While the cavity operates at dissipative solitons state, the reverse saturable absorption effect increases the maximum pulse energy from 11 to 13 nJ and plays a key role in transforming the pulse states, which further facilitates the generation of dissipative soliton resonance pulses. In addition, the reason of the different influences on pulses in two mode-locked regimes is also discussed. Our results reveal the role and promote the rational use of the reverse saturable absorption effect in different mode-locked regimes.

Square-wave pulse in 2-μm all-polarization-maintaining passively mode-locked fiber laser

The dissipative soliton resonance (DSR) pulses are demonstrated experimentally in an all polarization-maintaining (PM) thulium-doped mode-locked fiber laser. The mode-locked operation is achieved using of the nonlinear amplifying loop mirror mechanism (NALM). Each loop of the apparatus includes an independently controlled amplifier and a section of gain fiber. The experiment is carried out at a central wavelength of 1969.8 nm and 3.5 ns as the maximum output pulse width. The time domain and spectrum characteristics of output pulse are analyzed with different positions of PM-1950 fiber in the NALM loop. In addition, the DSR pulse properties are experimentally verified by changing the length of the PM-1950 fiber spliced into the NALM loop. We have achieved environmentally stable mode-locked pulses at 3, 2.1, and 1.62 MHz corresponding to the maximum pulse energies of 6.8, 20, and 29.1 nJ. The output pulse is stable and robust at different ambient temperatures.

Simulation for Generation of Several Types of Pulses in an Yb-Doped Mode-Locked Fiber Laser

We numerically demonstrated six types of pulses in an Yb-doped fiber laser, including dissipative soliton (DS), dissipative soliton resonance (DSR), multipulse, noise-like pulse (NLP), breathing soliton and soliton explosion. The influence of cavity conditions on DSR pulse properties is discussed systematically. It is found that the change of the saturation power of saturable absorber (SA) could transform DSR into various types of pulses. Saturation power of SA and injected signal affect the number and shape of multipulse. Furthermore, the influence of the saturation power of SA and intra-cavity dispersion on pulse type is diagrammed intuitively. By properly adjusting the transmission curve of SA, breathing soliton and soliton explosion can be obtained as well.

Switchable operation of multiple solitons and dissipative soliton resonance in a C- and L-band mode-locked fiber laser

We report on the wavelength-switchable operation of multiple solitons and dissipative soliton resonance (DSR) in C- and L-band fiber lasers. Mode-locking operations can be alternatively switched between 1565 nm and 1604 nm with adjustments to the polarization controller. Through controlling the intracavity filtering effect, tunable operations have been observed from 1563.7 nm to 1574.6 nm and from 1600.3 nm to 1605.7 nm. More importantly, the fiber laser operated at the 1565 nm waveband tended to generate multiple solitons, whereas one operated at the 1604 nm waveband tended to generate a rectangular DSR. Our investigations may contribute to understanding complex soliton dynamics in fiber lasers.

Dissipative-Soliton-Resonance generation in anomalous-dispersion fiber lasers based on spectral filtering effect

In this article, we numerically research the generation of Dissipative-Soliton-Resonance (DSR) pulse in anomalous dispersion regime based on spectral filtering effect. We find that a strong spectral filtering effect can limit the spectrum broadening and avoid the pulse breaking up in the high effective gain of the cavity, which leads to the formation of DSR pulse. Meanwhile, we also find that the peak power of DSR pulse increases with the saturation power, which is in line with the case in normal dispersion regime. As a comparison, the DSR pulse cannot be obtained in the absence of spectral filtering effect, which proves that the generation of DSR pulse needs strong spectral filtering effect in anomalous dispersion regime. We believe that our work can be served as a theoretically guideline to investigate the generation of DSR pulse in anomalous dispersion regime.

Harmonic dissipative soliton resonance in an Yb doped fiber laser with 110 W all fiber polarization-maintaining amplifier

The formation of harmonic dissipative soliton resonance (DSR) is experimentally investigated in an Yb-doped fiber laser operating in large normal dispersion regime. The DSR is observed at a fundamental frequency of 221 KHz, which delivered square-shaped with of 18.7–98.5 ns and single pulse energy of 0.25 μJ at 1056 nm. By adjusting the PCs, the DSR square pulses could be split into their harmonic mode-locked (HML) counterparts. These experimental results provide a new viewpoint for the further understanding of the mechanism and characteristics of HML square pulses. Based on a two-stage all-fiber PM master oscillator power amplifier (MOPA) system seeded by this oscillator, the pulses are amplified up to 110 W output power with the polarization extinction ratio (PER) of 18.7 dB at different frequencies ranging from 221KHz to 663 KHz and a record pulse energy of 0.51 mJ at the frequency of 221 KHz is achieved.

Breach and recurrence of dissipative soliton resonance during period-doubling evolution in a fiber laser

We report on the experimental observation of period-doubling bifurcation of dissipative-soliton-resonance (DSR) pulses in a fiber laser passively mode-locked by using the nonlinear optical loop mirror. Increasing the pump power of the fiber laser, we show that temporally a stable, uniform DSR pulse train could be transformed into a period-doubling state, exhibiting two sets of pulse parameters between the adjacent cavity roundtrip. It is found that DSR pulses in the period-doubling state could maintain the typical feature of DSR pulse: fixed pulse peak power and linear variation in pulse width with respect to the pump power change. The mechanism for achieving period-doubling of DSR pulses is discussed.

Two-dimensionally controllable DSR generation from dumbbell-shaped mode-locked all-fiber laser**Project supported by the National Natural Science Foundation of China (Grant Nos. 61435009, 61235008, and 61405254).

An all-fiber dumbbell-shaped dual-amplifier mode-locked Er-doped laser that can function in dissipative soliton resonance (DSR) regime is demonstrated. A nonlinear optical loop mirror (NOLM) and a nonlinear amplifying loop mirror (NALM) are employed to initiate the mode-locking pulses. Unlike conventional single-amplifier structure, the output peak power of which remains unchanged when pump power is varied, the proposed structure allows its output peak power to be tuned by changing the pump power of the two amplifiers while the pulse duration is directly determined by the amplifier of nonlinear amplifying loop mirror. The entire distribution maps of peak power and pulse duration clearly demonstrate that the two amplifiers are related to each other, and they supply directly a guideline for designing tunable peak power DSR fiber laser. Pulse width can change from 800 ps to 2.6 ns and peak power varies from 13 W to 27 W. To the best of our knowledge, the peak power tunable DSR pulse is observed for the first time in dumbbell-shaped Er-doped all-fiber mode-locked lasers.

Numerical research on the dissipative-soliton-resonance peak power in normal-dispersion fiber lasers

In this article, the peak-power expression of dissipative-soliton-resonance (DSR) pulse is derived, in a normal-dispersion fiber laser, by using the equation for the resonance curve and the relationship between the parameters of cubic–quintic complex Ginzburg–Landau (CGLQ) equation and the cavity parameters. According to the peak-power expression, the peak power of DSR pulses is inversely proportional to the average dispersion and the square of the gain bandwidth, is proportional to the square of the saturation power. That is to say, we can improve the peak power of DSR pulse in three ways: Firstly, increase the saturation power in the case of sinusoidal-saturable-absorber transmission curve; secondly, decrease the gain bandwidth properly; thirdly, decrease the average dispersion suitably. In addition, the further results of numerical simulations are obtained by using pulse-tracing technique, which are in good agreement with the theoretical derivation of peak power of DSR pulses. This means that our work can serve as a guideline to design high-peak-power DSR fiber laser.

Dual-wavelength rectangular pulses in a mode-locked ytterbium-doped fiber laser

We demonstrate dual wavelength rectangular pulses in an ytterbium-doped fiber laser in a simple, all-fiber standing wave cavity configuration. The laser cavity consists of a nonlinear optical loop mirror as a saturable absorber at one end and two fiber Bragg gratings at the other end at wavelengths of 1025 and 1055 nm. There are three distinct regimes of operation in the cavity with an increase in the pump power, one where only 1025 nm wavelength pulses appear, then both 1025 and 1055 nm pulses are supported in the cavity after that, only 1055 nm wavelength pulses are present in the cavity. In the intermediate pumping regime, two sets of pulses are supported in the cavity. These pulses move in the cavity at different speeds and on the cross-over there is no interaction in the pulses. The mode-locked pulses at the 1025 nm wavelength are polarized, whereas pulses corresponding to 1055 nm are nearly unpolarized. Pulses corresponding to both the wavelength bands exhibit a dissipative soliton resonance signature. The laser generates 60 mW total average output power at the maximum pump power of 260 mW at a ∼1.8 MHz repetition rate. The presented cavity mechanism can be utilized to generate various dual- or multi-wavelength mode-locked pulses.

Dissipative Soliton Resonance in an All-Polarization Maintaining Fiber Laser With a Nonlinear Amplifying Loop Mirror

An all-polarization maintaining mode-locked Yb-doped fiber integrated laser with a nonlinear amplifying loop Mirror (NALM) under the operation regime of dissipative soliton resonance (DSR) has been demonstrated. The mode-locked laser can generate DSR pulses at 1.04 μm at the repetition rate of 2.59 MHz. The output DSR pulses can be tuned in pulse width from hundreds of picoseconds to a few nanoseconds by adjusting the pump power. By changing the pump power of the main loop and the NALM, the maximum output average power of 51.4 mW and the corresponding pulse energy about 20 nJ are achieved, respectively. Pulse breaking of the DSR pulses was observed apart from the typical pulse broadening at a fixed pulse peak power due to the peak power clamping effect, while solely increasing the main loop pump power. In addition, the characteristics of the DSR pulses such as pulse width, pulse energy, output power and optical spectrum with the changing of main loop pump power and NALM pump power are also discussed respectively.

Fe3O4 nanoparticle-enabled mode-locking in an erbium-doped fiber laser.

In this paper, we have proposed and demonstrated the generation of passively mode-locked pulses and dissipative soliton resonance in an erbium-doped fiber laser based on Fe3O4 nanoparticles as saturable absorbers. We obtained self-starting mode-locked pulses with fundamental repetition frequency of 7.69 MHz and center wavelength of 1561 nm. The output of a pulsed laser has spectral width of 0.69 nm and pulse duration of 14 ns with rectangular pulse profile at the pump power of 190 mW. As far as we know, this is the firsttimethatFe3O4 nanoparticles have been developed as low-dimensional materials for passive mode-locking with rectangular pulse. Our experiments have confirmed that Fe3O4 has a wide prospect as a nonlinear photonics device for ultrafast fiber laser applications.