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990 nm High-power High-beam-quality DFB Laser With Narrow Linewidth Controlled By Gain-coupled Effect
摘要： High-power single-longitudinal-mode regrowth-free gain-coupled distributed feedback laser diode based on ridge waveguide with periodic current injection is achieved at 990 nm. Our device is fabricated only by standard i-line lithography with micron-scale precision, obtains an excellent performance at high injection current. A continuous-wave power of over 0.681 W is achieved at 3 A. The maximum continuous-wave power at single-longitudinal-mode operation is up to 0.303 W at 1.4 A. Narrow linewidth emission has been reached with a 3 dB spectrum width less than 1.41 pm. The high side mode suppression ratio is over 35 dB. The lateral far field divergence angle is only 15.05 °, the beam quality factor M 2 is 1.245, achieving a laterally near-diffraction-limit emission. It is more beneficial for single mode fiber coupling as pumping sources and other applications which require high beam quality at high power with easy fabrication technique.
关键词： narrow linewidth,Single-longitudinal mode,Gain-coupled DFB,Semiconductor lasers
更新于2025-11-28 14:24:03
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A single-longitudinal-mode narrow-linewidth dual-wavelength fiber laser using a microfiber knot resonator
摘要： A stable narrow-linewidth dual-wavelength single-longitudinal-mode (SLM) erbium-doped fiber laser is demonstrated using a microfiber knot resonator (MKR). A MKR made by the microfiber knotting method exhibits the characteristics of flexibility, high quality factor and broad free spectral range and can be used as a comb-like ultra-narrow band pass filter. SLM operation of the fiber laser can be generated as a function of the Vernier effect by cascading a 650 μm diameter MKR in the ring cavity. In combination with a common fiber Bragg grating, narrow linewidths (0.016 nm and 0.019 nm) of dual wavelength are generated. Finally, a SLM ring laser with narrow linewidth and low-frequency noise is achieved. Simultaneous generation of first- and second-order optical vortex beams in the dual-wavelength fiber laser using different mode-selective couplers is demonstrated.
关键词： fiber lasers,fiber optics,optical communication
更新于2025-11-28 14:24:03
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Rectangular Pulse Generation from a Mode Locked Raman Fiber Laser
摘要： Rectangular and step-like pulses are generated in a mode locked Raman fiber laser with a nonlinear optical loop mirror. The Raman laser has a typical figure-8 configuration. Stable rectangular pulses with a fundamental repetition rate of 733 kHz are obtained. As the increasing of the pump power, the Raman pulse evolves to a step-like rectangular pulse. The maximum pulse energy is 64.1 nJ with a pulse width of 25.1 ns. After spectrally resolved measurements, the step-like pulse is proved to be induced by the dual wavelength oscillation. It is the first report of rectangular pulsed output in mode-locked Raman fiber laser to the best of our knowledge.
关键词： Laser mode locking,Raman scattering,Fiber lasers
更新于2025-11-28 14:24:03
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Multiplexed ultrafast fiber laser emitting multi-state solitons
摘要： Ultrafast fiber lasers have been serving as an ideal playground for spreading the extensive industrial applications and exploring the optics nonlinear dynamics. Here, we report a bidirectional fiber laser scheme for validating the possibility of a multiplexed laser system, which is passively mode-locked by the nonlinear polarization rotation (NPR) technique. In particular, the proposed fiber laser consists of one main cavity and two counter-propagating branches with different dispersion distributions. Thus, different formation mechanisms are introduced into the lasing oscillator. Consequently, stable conventional solitons (CSs) and dissipative solitons (DSs) are respectively formed in the clockwise (CW) and counterclockwise (CCW) directions of the same lasing oscillator. Moreover, attributing to the strong birefringence filtering effect, the wavelength selection mechanism is induced. Through the proper management of intra-cavity birefringence, wideband wavelength tuning and switchable multi-wavelength operations are experimentally observed. The central wavelength of CS can be continuously tuned from 1560 nm to 1602 nm. Additionally, the evolution process of different multi-wavelength operations is also elucidated. Benefiting from this multiplexed laser scheme, bidirectional lasing oscillation, multi-state soliton emission, wavelength tuning and multi-wavelength operations are synchronously realized in a single laser cavity. To the best of our knowledge, it is the first time for such a multiplexed fiber laser has been reported. The results provide information for multifunctional ultrafast fiber laser system, which is potentially set for telecommunications, fiber sensing and optics signal processing, etc.
关键词： multi-wavelength operations,nonlinear polarization rotation,wavelength tuning,Ultrafast fiber lasers,dissipative solitons,conventional solitons
更新于2025-11-28 14:24:03
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Passively Q-Switched All-Fiber Yb-Doped Lasers Based on Nonlinear Multimode Interference?
摘要： We report a passively Q-switched all-?ber Yb-doped laser using the structure of step-index multimode ?ber and graded-index ?ber (SIMF-GIMF) as a new saturable absorber (SA) based on the nonlinear multimode interference (NL-MMI). Through bending the SA to a certain state, we obtain a stable Q-switched laser operation with the shortest pulse duration of 4.37 μs and a corresponding repetition rate of 147.6 kHz with center at 1,039 nm. The maximum average output power and single pulse energy are recorded to be 2.409 mW and 16.3 nJ, respectively. To the best of our knowledge, this paper con?rms experimentally for the ?rst time Q-switched laser operation based on SIMF-GIMF SA in all-?ber lasers. In addition, we also observed unstable Q-switched mode-locking operation. All-?ber lasers based on SIMF-GIMF SA are attractive for practical applications and undergo no damage and performance degradation with time.
关键词： multimode ?bers,all-?ber Yb-doped lasers,Q-switched operation
更新于2025-11-28 14:24:03
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Observation of evolution dynamics from bound states to single-pulse states in a passively mode-locked fiber laser
摘要： We report what is, to our knowledge, the first experimental observation of the ultrafast evolution dynamics from bound states (BSs) to single-pulse states (SPSs) by using the dispersive Fourier-transform (DFT) technique. The evolutions from three categories of initial BSs to SPSs are spectrally resolved in real time. Usually, accompanied by complex soliton–soliton interaction and competition, one of the two bound pulses weakens to disappearance, and the other one evolves into SPS. During the transition, the two bound pulses ordinarily depart away from each other with complex changes of relative phase. However, it is found that not all the evolutions are accompanied by the increase of temporal separation between two bound pulses. The obtained results would facilitate a deep understanding of complex dynamics in nonlinear systems and provide valuable data for further theoretical studies.
关键词： single-pulse states,bound states,fiber lasers,Ultrafast evolution dynamics
更新于2025-11-28 14:24:03
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Dual-wavelength passively mode-locked Yb-doped fiber laser based on a $\text{SnSe}_2$-PVA saturable absorber
摘要： In this paper, tin diselenide (SnSe2) was successfully prepared with liquid phase exfoliation method and embedded into polyvinyl alcohol (PVA) as a saturable absorber (SA) in a dual-wavelength passively mode-locked Yb-doped fiber laser. Stable mode-locked pulses with a maximum average output power of 2.55 mW and a slope efficiency of 1.3% at the fundamental repetition rate of 333 kHz were achieved. By properly adjusting polarization state, four kinds of dual-wavelength fundamental frequency mode-locked pulses with peak wavelength intervals of 0.4, 1.0, 1.5 and 1.9 nm were obtained, and corresponding waveforms with different single pulse shapes were investigated in our work. A maximum signal to noise ratio (SNR) of 71.04 dB indicates that SnSe2 is promising to serve as SA in passively mode-locked fiber lasers.
关键词： Fiber lasers,Mode-locked lasers,Diode-pumped lasers
更新于2025-11-28 14:23:57
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Diode-pumped single-pass tunable mid-infrared gas Raman source by methane-filled hollow-core fiber
摘要： We report here, to the best of our knowledge, the first diode-pumped single-pass tunable mid-infrared fiber gas Raman laser source using methane-filled hollow-core fibers. Pumped by a homemade tunable high peak-power amplified diode laser, whose wavelength covers the range of 1540 nm to 1560 nm, the mid-infrared laser emission over the range of 2796 nm to 2863 nm is generated by the stimulated Raman scattering of methane molecules. The highest average output power of ~34 mW at 2829 nm is achieved with 14.2 m fiber at 16 bar when pumped at 1550 nm. This paper opens new opportunities for compact tunable mid-infrared fiber lasers.
关键词： gas lasers,Raman lasers,fibre lasers,stimulated Raman scattering
更新于2025-11-28 14:23:57
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Direct oscillation at 640-nm in single longitudinal mode with a diode-pumped Pr:YLF solid-state laser
摘要： A diode-pumped solid-state laser directly emitting continuous-wave (cw), single-longitudinal mode (SLM) output at 640-nm with a c-cut praseodymium-doped yttrium lithium fluoride (Pr:YLF) crystal was demonstrated for the first time, to the best of our knowledge. Combining two quarter-wave plates (QWPs) and one Brewster plate to form a twisted-mode cavity, this SLM solid-state laser achieved a maximum cw output power of 403 mW with a threshold of 600 mW and a slope efficiency of 26.8%. The emission spectrum had a linewidth of 150 MHz. The single-mode beam quality (M2) was 1.10 and 1.07 along the x and y direction, respectively.
关键词： Single-longitudinal-mode,Diode-pumped solid-state lasers,Visible lasers
更新于2025-11-28 14:23:57
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Tungsten disulfide saturable absorber for passively Q-Switched YVO4/Nd:YVO4/YVO4 laser at 1342.2 nm
摘要： By using both tungsten disul?de saturable absorber (WS2-SA) and YVO4/Nd:YVO4(0.3 at.%)/YVO4 crystal, a passively Q-switched laser centered at 1342.2 nm is ?rst reported. Stable Q-switched pulses can be obtained. At the pump power of 12 W, a shortest pulse width of 550 ns and a pulse repetition rate of 97 kHz can be observed by a digital oscilloscope, corresponding to maximum pulse energy of 5.55 μJ and pulse peak power of 10.1 W. The results promote the promising applications of WS2-SA in all-solid-state laser at 1.3 μm.
关键词： WS2 saturable absorber,Diode-pumped lasers,Q-switched lasers,1342.2 nm laser
更新于2025-11-28 14:23:57