Dissipative Soliton Resonance Research Articles

2.1 μm Band Dissipative Soliton Resonance Mode-Locked Ho-Doped Tunable Fiber Laser

We report a 2.1 μm band mode-locked holmium-doped fiber (HDF) laser with tunable wavelength and pulse width in dissipative soliton resonance (DSR) region for the first time to our knowledge. A piece of HDF is pumped by a home-made 1.9 μm band fiber source, and a nonlinear-amplifying-loop-mirror structure is used to realize mode-locking operation with net anomalous dispersion. The repetition rate of pulse is 8.97 MHz. The pulse duration can be adjusted from 1.16 to 3.93 ns with the increase of pump power, while maintains a constant peak power. At the maximum pump power of 2.1 W, the pulse energy is up to 2 nJ. Moreover, the central wavelength is in the tunable range from 2054.4 to 2076 nm by appropriately adjusting the polarization controllers. We also explore the nonlinear correlation characteristic of DSR pulse by changing the length of high nonlinear fiber.

Generation of dissipative soliton resonance and pulse burst in an Nd-doped all-fiber mode-locked laser operating at 910 nm

Macro-bending of optical fiber makes bending loss increase at longer wavelength, so the 1.06 μm laser can be suppressed without affecting 0.9 μm laser emission. In this paper, it is implemented as a new approach to suppress 1.06 μm laser emission and produce 0.9 μm laser in an Nd-doped single-mode all-fiber mode-locked laser. Dissipative soliton resonance (DSR) pulses with pulse width increasing from 1.46 ns to 6.33 ns are generated in the Nd-doped all-fiber mode-locked laser operating at 0.9 μm. Besides that, the 0.9 μm pulse burst with pulse number of 1–3 is generated.

Vector Staircase Noise-Like Pulses in an Er/Yb-Codoped Fiber Laser

We report on the experimental observation of vector staircase noise-like pulses (NLPs) produced by an Er/Yb-codoped fiber laser with a nonlinear optical loop mirror (NOLM) as the saturable absorber (SA). The staircase NLPs consist of two rectangular pulses with different energies and durations, such that the two pulse widths both increase linearly with increasing pump power with an almost constant slope while the pulse amplitude remains constant, similar to the case with Dissipative Soliton Resonance pulses. The polarization rotation state of the staircase NLPs has also been investigated along with multiple polarization dynamic patterns, including group velocity locked and polarization locked states. We have also observed harmonic mode-locked (HML) staircase NLPs by carefully adjusting the orientation of the intra-cavity polarization at fixed pump power. It was found that the HML staircase NLPs were identical to the fundamental staircase NLPs as regards the vector character and the changes in pulse duration. The experimental results are expected to enrich understanding of the vector nature of staircase NLPs and may lead to a new laser source for material processing.

Programmable high-order mode control method based on acoustically induced fiber grating.

We demonstrate a programmable high-order mode control method that can be implemented in high-power fiber lasers. 2 W average-power mode-locked pulses are obtained based on a mode-locked fiber laser working in dissipative soliton resonance regime. The fundamental mode (LP01) is fully or partially converted to the high-order modes (LP11a/b) via an acoustically-induced fiber grating. The mode-superposition fields are recorded using an optical 4f system, and mode components are subsequently analyzed by a mode decomposition algorithm. Our experiments suggest that the mode patterns are stable and dynamically switchable. The method is expected to possess good application value in optical tweezers, fiber communication, laser material processing and other research fields.

Dual-wavelength harmonic mode-locked dissipative soliton resonance of Yb fiber laser

Dissipative soliton resonance (DSR) mode-locked fiber lasers have stimulated great interest recent years due to their unique pulse-breaking-free advantage for scaling soliton pulse energy. However, the mechanism accounting for pulse breaking to generate multipulses in DSR fiber lasers has not reached a consensus. Here, we show that harmonic mode-locked DSR 1-μm Yb-doped fiber laser in the dual-wavelength regime can be realized with a semiconductor saturable absorber mirror (SESAM). In the fundamental frequency (3.5 MHz) mode-locked state, the pulse width continuously broadens from 2 to 8.9 ns as the output power increases from 1.26 to 5.1 mW (pulse energy being from 0.36 to 1.46 nJ), while the pulse peak power is clamped at 0.17 W, highlighting the typical characteristics of DSR mode-locking operation. Through simply adjusting the SESAM’s feedback conditions, the DSR fiber laser can transits from the fundamental-frequency mode locking to harmonic mode-locked states. Harmonic states from the 2nd to 9th order have been observed, with pulse repetition rate enhanced from 7 to 31.5 MHz. Under fixed pump power, increasing harmonic orders leads to reduction of the pulse width and pulse energy but does not change the unique quantization feature of the peak power. The status of the SESAM also guarantees the generation of dual wavelengths centered at 1072.5 and 1079.5 nm with spectral widths of 2.7 and 1.9 nm, respectively. This dual-wavelength harmonic mode-locked DSR Yb fiber laser can find applications in various areas.

Pulse Shape Estimation in a DSR Fiber Laser Using the Genetic Algorithm

Exploiting the computing power of the genetic algorithm, a numerical study of dissipative soliton resonance (DSR) in a ring laser mode-locked by a real saturable absorber (SA) is conducted. A section of photonic crystal fiber (PCF) is inserted into the laser cavity design to facilitate accurate control of both dispersion and nonlinearity. The influence of the cavity parameters on the evolution of the DSR pulses is systematically analyzed. The genetic algorithm demonstrates that the generation of DSR square pulses depends directly on the PCF dispersion, the PCF nonlinearity, the PCF length, and the modulation depth of the SA. Finally, the sensitivity of the DSR pulse width, peak power and energy to perturbations in a few key design parameters are highlighted.

High-power yellow DSR pulses generated from a mode-locked Dy:ZBLAN fiber laser.

Ultrafast yellow lasers are in high demand in recent biomedical and medical applications; however, direct emission of mode-locked pulses in yellow at the high-power level still presents a huge technical challenge to date. By integrating the nonlinear polarization rotation (NPR) scheme into a Dy:ZBLAN fiber laser, dissipative soliton resonance pulses at ∼575 nm are demonstrated for the first time, to the best of our knowledge. The average output power reaches ∼240 mW at maximum, which is an improvement of almost two orders of magnitude over those reported from the latest mode-locked visible fiber lasers. The laser scheme combines a piece of large-core Dy:ZBLAN gain fiber and free-space NPR components designated at the yellow bandwidth. The maximal pulse energy is 2.4 nJ at the repetition rate of ∼100 MHz and the minimal pulse duration is 83 ps. The achieved wavelength of 575 nm is the shortest ever reached from a fiber-based mode-locked laser to date.

Pulse shrinkage of dissipative-soliton-resonance pulses with or without period doubling

Dissipative soliton resonance (DSR) is a promising operation regime in fiber lasers where unlimited pulse energy boost is expected. However, several phenomena classified as anti-DSR performance were reported recently. Here pulse shrinkage of DSR pulses is investigated in a fiber laser. By setting a central-wavelength-drifting Gaussian filter, after DSR performance of pulse broadening with increasing gain, the pulse shrinkage occurs when the gain continues to increase. A central-wavelength-drifting bimodal filter can also achieve pulse shrinkage. In addition, pulse shrinkage together with period doubling can be observed by changing the initial settings.

Review of ultrafast fiber oscillators based on Mamyshev and dissipative soliton resonance mechanisms

This work presents a comparative review of two classes of advanced, ultrafast, fiber lasers: dissipative soliton resonance (DSR) oscillators and Mamyshev oscillators. These two classes have received significant attention in recent years and have arguably the highest potential among new ultrafast fiber oscillators, which motivated this work. Working principles are carefully described, and the mechanisms used to mitigate or exploit nonlinearity are highlighted and discussed. An analysis of existing laser systems based on the two classes is performed, with focus on pulse duration, energy, and peak power. Examples of both classes based on ytterbium-, erbium-, and thulium-doped fibers are presented. It is found that the DSR laser generally achieves higher pulse energies than the Mamyshev oscillator, but the latter results in shorter pulse durations. Finally, it is concluded that Mamyshev oscillators perform better in terms of peak power and stability since they do not rely on suppressing nonlinearity. Suggestions for further improvements are made.

Highly Efficient Multiple Watt Gain-Switched 1.7 μm All-Fiber Laser Pumped by 1.6 μm Harmonic Dissipative Soliton Resonance Pulses

Here, we firstly utilize a newly explored 1.6 μm harmonic dissipative soliton resonance (DSR) pulses as a pump source to realize a highly efficient gain-switched thulium fiber laser at 1719.52 nm. The 1.6 μm DSR pulses with a fundamental repetition rate of 360 kHz were produced from a nonlinear amplifying loop mirror (NALM) ring cavity, which directly output high power mode-locking pulses due to freedom of soliton-area limitation and pulse breaking. The harmonic mode-locking (HML) operation was achieved by properly adjusting the polarization controllers (PCs). The thulium fiber laser cavity constructed by a Fiber Bragg Grating (FBG) pair was resonantly (in-band) pumped by the 1.6 μm harmonic DSR pulses. Taking the merit of the strong absorption of Tm^3+ at 1.6 μm and the laser cavity having a low insert loss, the 1.7 μm gain-switched fiber laser with the maximum repetition rate of 2.16 MHz, corresponding to the average power of 2.826 W and the pulse energy of 1.33 μJ, was obtained at a high slope efficiency of about 71.9%. The maximum output power could exceed 3 W with a high slope efficiency of over 70%, which is the record in 1.7 μm all-fiber pulsed thulium lasers.

Hectowatt-level GHz burst-mode all-fiber laser based on dissipative soliton resonance.

We demonstrate a high power Yb-doped burst-mode all-fiber laser system operating at GHz intra-burst repetition rate. To our knowledge, it is the first report utilizing dissipative soliton resonance (DSR) to generate tunable burst-mode rectangular pulses. Due to the tunable duration and the rapid rise/fall time for DSR pulses, a 1-10 ns adjustable burst pulse duration is achieved. The intra-burst with sinusoidal waveform can be tuned from 0.8 GHz to 1.5 GHz and actively modulated by an electro-optic modulator (EOM). Amplified by a three-stage Yb-doped fiber amplifier (YDFA), the output power achieves 304 W at 10 ns of burst duration, and the maximum peak power reaches over 50 kW at 2 ns of burst duration. This laser system is anticipated to be applied to generate high power arbitrary microwave signal.

Dissipative Soliton Resonance and Noise-Like Pulse in a Self-Pulsing Fiber Laser

Dissipative Soliton Resonance and Noise-Like Pulse in a Self-Pulsing Fiber Laser

Dissipative soliton resonance and noise-like pulse generation of large normal dispersion Yb-doped fiber laser

In this paper, we experimentally demonstrate two types of dissipative soliton resonant (DSR) and noise-like pulse (NLP) in a mode-locked fiber laser using the nonlinear optical loop mirror (NOLM). By appropriately adjusting the polarization states, the switchable generation of DSR and NLP can be achieved from one mode-locked fiber laser. By adjusting the pump power, the pulse width of DSR increases gradually from 2.45 to 13.35 ns with a constant peak intensity, while the NLP just has a little increase, even splitting into two narrower pulses at higher pump power. Two types of DSR and NLP have the same pulse periods of 1.29 μs, corresponding to the cavity length of the fiber laser. The obtained results display the evolution process of DSR pulse and NLP in mode-locked fiber laser and have some application in optical sensing, spectral reflectometry, micromachining, and other relative domains.

Impact of reverse saturable absorption on pulse dynamics in the ultrafast fiber laser

In this work, we present a numerical investigation of the pulse dynamics in an all-normal dispersion fiber laser mode-locked by a physical saturable absorber. We erected a theoretical model including the reverse saturable absorption (RSA) and spectral filtering effects. Utilizing the double-parameter scanning method, the pulse state distribution is mapped in the two-dimensional parameter space. The simulation results emphasize that the RSA greatly affects the transitions of pulse states and pulse properties. Moreover, we explore the multipulse region in detail and then demonstrate two completely different multipulse evolution dynamics. Based on this, we offer an analysis of dissipative soliton resonance multipulse generating in the physical saturable absorber-based ultrafast fiber laser.

Generation of rectangular pulses in ytterbium-doped fiber laser based on a SnSe2 saturable absorber

Based on an as-prepared high-quality tin diselenide-polyvinyl alcohol (SnSe2-PVA) saturable absorber (SA), the stable rectangular pulses operating at the dissipative soliton resonance (DSR) region were observed in a passively mode-locked ytterbium-doped fiber (YDF) laser at the center wavelength of 1062.3 nm. The laser characteristics versus the pump power were investigated experimentally. As the pump power increased, the wave-breaking-free DSR pulse width varied from 20.5 ns to 44.7 ns. At the pump power of 365 mW, the maximum pulse energy of the DSR pulse is 0.928 nJ, corresponding to a signal to noise ratio (SNR) up to 74 dB. The results demonstrate the excellent saturable absorption performance of SnSe2 in generating the DSR pulses in fiber lasers.

Nd-Doped Polarization Maintaining All-Fiber Laser With Dissipative Soliton Resonance Mode-Locking at 905 nm

Moving the fiber laser emission to the region below one micron may provide a cheaper, more compact and robust alternatives to the existing solid state lasers. Here, for the first time we report a neodymium mode-locked fiber laser emitting at 905 nm in the all-fiber polarization maintaining configuration. We obtain a self-starting pulse generation in nonlinear amplifying loop mirror (NALM) cavity configuration. To suppress a dominant emission at 1064 nm corresponding to a 4-level laser scheme, we use an active fiber - 920/1064 division multiplexer - active fiber sandwich-like sequence in the NALM loop. A rectangular shape dissipative soliton had nJ energy, 30 pm spectral width and 80 - 430 ps width linearly depending on the pump power. Excellent agreement with numerical simulation allowed us to recover pulse shape and width for the pulses out of autocorrelation window.

3 W average-power high-order mode pulse in dissipative soliton resonance mode-locked fiber laser

AbstractRecently high-order modes (HOMs) lasers have been extensively investigated due to their potential applications in mode-division multiplexing. In this paper, we present two schemes of generating HOMs from the mode-locked fiber lasers (MLFLs) in the dissipative soliton resonance (DSR) regime. Watt-level HOM outputs are implemented through intra-cavity mode conversion. 3 W average-power HOMs with an efficiency slope of 25% can be obtained based on an MLFL in the DSR regime, which is achieved by incorporating a long-period fiber grating (LPFG) and a dual-resonant acoustically induced fiber grating (AIFG), respectively. Their different spectrum responses enable flexible mode conversion in the MLFLs. Both fiber mode converters are exploited to show their robust capability of efficient mode manipulation. The MLFL with an LPFG inserted in the cavity can achieve wide-bandwidth intra-cavity optical vortex beams (OVBs) near the dispersion turning around point because of the pulses of the fundamental mode and high-order vortex eigenmodes oscillating in the cavity with the same group velocity to form spatiotemporal mode locking. The MLFL based on a dual-resonant AIFG can perform the function of fast switching (∼0.3 ms) in LP01, LP11a, and LP11bmodes with a high modal purity of 96%. These different modes with high-energy pulses can be flexibly switched with programmable radio frequency modulation. Furthermore, a quarter-wave plate and a polarizer are employed at the output of fiber laser to realize the controllability of the mode field, which is possible to generate a controllable mode field of OVBs based on the first-order Poincaré sphere. This control method can be integrated with the MLFLs to extend the flexibility of high-power HOMs generation.

Q-switched dissipative soliton resonance operation in GeTe based fiber laser

Q-switched dissipative soliton resonance (DSR) operation in a germanium telluride (GeTe) based erbium-doped fiber laser is investigated experimentally. The modulation depth of the GeTe based saturable absorber is about 12.3%. For the Q-switched envelope of the DSR operation in this laser, its repetition rate increases monotonically from 6.95 to 14.09 kHz and full-width at half-maximum decreases from 24.46 to 18.37 μs when pump power changes from 39.1 to 101.1 mW. With increase of pump power, the width of DSR pulse increases from 13.3 to 20.7 ns, and the average output power varies from 1.1 to 2.1 mW. The highest average single-pulse energy of DSR is calculated as 2.44 nJ at pump power of 101.1 mW. This result show that Q-switched DSR operation can be obtained in a nanocrystal based fiber laser, which will broaden the application of nanocrystals in fiber lasers.

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.