- 标题
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Explosion induced rogue waves and chaotic multi-pulsing in a passively mode-locked all-normal dispersion fiber laser
摘要： In this work, an experimental study of non-stationary pulse dynamics consisting of explosion events and chaotic multi-pulsing from an all-normal dispersion Yb-fiber laser operating in noise-like pulse (NLP) state have been reported. During explosion in NLP state, which resembled soliton explosion, dispersive Fourier transform measurements revealed large, intermittent amplitude fluctuations in the real-time spectrum indicative of rogue waves. The fluctuations either appeared randomly at the lasing wavelength within the Yb-gain spectra or at the frequency downshifted Raman Stokes wavelength. It was also observed that such fluctuation at the Raman wavelength could even exceed the amplitude of the spectral components at the main lasing wavelength. With suitable adjustments, the laser operation could be switched to chaotic multi-pulsing state where the acquisition of a large number of consecutive roundtrips revealed inter-pulse motion with unique trajectories occurring over millisecond time scales.
关键词： optical rogue waves,multi-pulsing,non-stationary pulse dynamics,noise-like pulse,fiber lasers,mode-locked fiber lasers,non-linear dynamics
更新于2025-09-23 15:21:01
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Sub-200-kHz single soliton generation in a long ring Er-fiber laser with strict polarization control by using twisted fiber
摘要： In the present work we demonstrate a novel single-soliton ultra-low pulse repetition frequency passively mode-locked erbium-doped fiber laser. We mitigate the residual linear birefringence of fiber by fiber twist to achieve a strict control of polarization. For mode-locking the nonlinear polarization rotation (NPR) was used. Special technique was applied to reduce the overdriving of NPR that allows the generation of single soliton in ultra-long cavity. The strict control of polarization yields a stable relation between the polarization state of the pulses propagating in the cavity and the regimes of generation. A 192.12-kHz train of soliton pulses was obtained with pulse duration of 4.7 ps at 1560.1 nm, the average power was 29 μW and the estimated peak power was ? 30.8 W with an energy of 150.9 pJ.
关键词： Ultra-long laser cavity,Solitons,Nonlinear optics,Overdriving nonlinear effects,Mode-locked fiber lasers
更新于2025-09-23 15:19:57
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2.4 GHz L-Band Passively Harmonic Mode Locked Er-Doped Fiber Laser Based on Carbon Nanotubes Film
摘要： We experimentally demonstrate a passively harmonic mode locked (PHML) Er-doped fiber laser with pump power efficiency up to 17 MHz/mW operating at L-band based on single walled carbon nanotubes polyvinyl alcohol (SWCNTs-PVA) film. Under 233 mW pump power, the stable pulse train at 1594.97 nm with 40.5 dB side mode suppression ratio (SMSR) and 742 fs pulse duration is obtained at a repetition rate of 1.923 GHz, corresponding to 170th harmonic of the fundamental frequency. Under optimized intracavity conditions, the pulses frequency is able to scale up to 2.415 GHz with a high level of 40 dB SMSR, which to the best of our knowledge, is the highest value yet reported from a L-band PHML fiber laser incorporating SWCNTs as saturable absorber (SA). Such high repetition rate and stable fiber laser operating at L band may be desirable for various applications.
关键词： nanomaterials.,Mode locked fiber lasers,mode locking
更新于2025-09-19 17:13:59
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[IEEE 2019 18th International Conference on Optical Communications and Networks (ICOCN) - Huangshan, China (2019.8.5-2019.8.8)] 2019 18th International Conference on Optical Communications and Networks (ICOCN) - Raman Dissipative-soliton Generation with a Nonlinear Optical Loop Mirror in a Polarization Maintaining Fiber Cavity
摘要： We report a Raman dissipative soliton generated in a mode-locked fiber laser with a nonlinear optical loop mirror. This configuration provides a method to obtain linearly polarized ultrafast laser at flexible wavelengths.
关键词： Raman scattering,nonlinear optical loop mirror,Mode-locked fiber lasers
更新于2025-09-16 10:30:52
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Breathing dissipative solitons in mode-locked fiber lasers
摘要： Dissipative solitons are self-localized coherent structures arising from the balance between energy supply and dissipation. Besides stationary dissipative solitons, there are dynamical ones exhibiting oscillatory behavior, known as breathing dissipative solitons. Substantial interest in breathing dissipative solitons is driven by both their fundamental importance in nonlinear science and their practical applications, such as in spectroscopy. Yet, the observation of breathers has been mainly restricted to microresonator platforms. Here, we generate breathers in a mode-locked fiber laser. They exist in the laser cavity under the pump threshold of stationary mode locking. Using fast detection, we are able to observe the temporal and spectral evolutions of the breathers in real time. Breathing soliton molecules are also observed. Breathers introduce a new regime of mode locking into ultrafast lasers. Our findings may contribute to the design of advanced laser sources and open up new possibilities of generating breathers in various dissipative systems.
关键词： spectroscopy,breathing solitons,mode-locked fiber lasers,dissipative solitons,nonlinear science
更新于2025-09-12 10:27:22
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Microfiber-Knot-Resonator-Induced Partial Elimination of Longitudinal Modes in fiber lasers for in-Tune-Switchable Nanosecond Pulse Generation
摘要： By incorporating a house-made microfiber knot resonator (MKR), mode-locking regime transformation in an erbium-doped fiber (EDF) laser was achieved. With typical nonlinear polarization rotation (NPR) as the mode-locker, ~890 fs soliton pulses could be directly produced from the EDF laser. However, once the MKR was further incorporated in it, the emitted pulse duration fell into the nanosecond regime, and meanwhile the spectral bandwidth dramatically narrowed down around 0.05 nm. This resulted from that the longitudinal laser modes were greatly eliminated by the MKR. The MKR exhibits tightly-packed, extremely narrow transmission teeth, acting as a comb-like, sharp-rolloff bandpass filter. The mode elimination factor could reach ~98.81%. Further manipulating the intra-cavity polarization state, the emission wavelength could be switchable from one of the transmission teeth of the MKR to another, due to the intrinsic polarization-sensitivity of the NPR. Our results demonstrated that MKR could be a useful device in fiber lasers to enable some artificially pre-defined spectral and temporal characteristics through pre-designing on the related parameters of the MKR. This could also provide a route to transform the temporal characteristics through tailoring the spectral profile, i.e., manipulating the permitted longitudinal laser modes, in fiber lasers.
关键词： Microfiber knot,mode-locked,Fiber lasers
更新于2025-09-12 10:27:22
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Femtosecond Soliton Erbium-doped Fiber Laser with a Symmetrical GIMF-SIMF-GIMF Saturable Absorber
摘要： A femtosecond soliton erbium-doped fiber ring laser with the symmetrical saturable absorber (SA) of graded index multimode fiber-step index multimode fiber-graded index multimode fiber (GIMF-SIMF-GIMF) is proposed and proved. Based on the nonlinear multimode interference (NL-MMI) effect of SA, the fiber laser achieved femtosecond soliton mode-locking operation and repetition rate tuning. The duration of soliton was 364 fs at 1562.5 nm and repetition rate was tunable from 10.29 MHz to 763.36 MHz. In the structure of SA, a short step index multimode fiber (SIMF) was inserted between two graded index multimode fibers (GIMFs) to generate more high-order modes，adjust the self-focusing length, and improve operation stability of mode-locked fiber laser. The SA also has the advantages of immunity to the external environment variation, high damage threshold and inoxidizability, which make the laser operate stably for a long time.
关键词： Femtosecond soliton,ultrafast fiber lasers.,mode-locked fiber lasers,nonlinear multimode interference
更新于2025-09-11 14:15:04
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Saturable Absorption with CNT Coupled WGM and Fabrication of Er-Doped Microresonator for on-Chip Mode-Locked Laser
摘要： Mode-locked (ML) fiber lasers are becoming key components in industry, because they provide high performance while being relatively inexpensive. The generation of high-repetition rate pulses is gaining interest but it remains a challenge to achieve a GHz repetition rate with fiber lasers. On the other hand, whispering-gallery-mode (WGM) microresonators allow the strong confinement of light and miniaturizing an ML laser into a WGM microresonator will enable us to achieve a high pulse repetition rate, a small footprint and on-chip integrability. In this work, we explore the possibility of a passive ML laser with the system shown in Fig. 1(a). There are two key technologies involved; one is saturable absorption (SA) and the other is laser gain in a microresonator. First, we verified numerically that we could realize an ML laser with our proposed carbon nanotube (CNT) coupled erbium (Er) doped microresonator, and the result is shown in Fig. 1(b). We modelled our system with a nonlinear Schr?dinger equation, where we took gain and SA (also loss (Q), Kerr effect, and dispersion) into account [2]. The result shows that a self-starting ML is possible with microresonator parameters. Next, encouraged by the numerical result, we experimentally demonstrated SA in a microtoroid. We grew CNTs selectively on a silica microtoroid by chemical vapor deposition and investigated the SA behavior (Fig. 1(c)). By performing a pump-probe like experiment we successfully characterized the SA behavior in a microresonator system. This is the first demonstration of SA in a WGM microcavity system [1]. We then fabricated an Er-doped active microtoroid by using the sol-gel method. The sol-gel method is one way of forming silica from a metal alkoxide precursor. Although sol-gel has been widely used, it is still a challenge to fabricate high-quality defect-free film on a Si wafer that allows us to fabricate an ultrahigh-Q WGM microresonator. Figure 1(d)-(f) shows the fabricated films. We found optimum parameters and obtained a clean film as shown in Fig. 1(g). By using this film, we fabricated an Er-doped WGM microresonator, where the Q was 1.2×106 at 1480 nm (Fig. 1(h)). We obtained clear up-conversion luminescence when we pumped the cavity at 1480 nm, which constitutes the first step towards ML lasing in such a WGM microresonator. In summary, these results provide a promising approach for realizing an on-chip high repetition rate ML WGM microresonator.
关键词： saturable absorption,sol-gel method,carbon nanotube,whispering-gallery-mode microresonators,erbium-doped microresonator,Mode-locked fiber lasers
更新于2025-09-11 14:15:04
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Super Gaussian pulse generation in a passively mode-locked fiber laser
摘要： The generation of self-similar super Gaussian-like pulses from a passively mode-locked fiber laser is numerically demonstrated. The laser cavity utilizes a long period fiber grating as a pulse-shaping element. The model is based on the normalized complex Ginzburg-Landau equation and the nonlinear coupled mode equations of the grating. The numerical results show stable super Gaussian pulses with a linear frequency chirp, a 1.5 ps pulse duration and 2 nJ energy. The generated pulses are scalable and exhibits no bifurcation or instability as the gain is increased.
关键词： Mode-locked fiber lasers,Ginzburg-Landau equation,Kerr nonlinearity,Self-similar pulses,Numerical methods
更新于2025-09-11 14:15:04