- 标题
- 摘要
- 关键词
- 实验方案
- 产品
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A chaotic state in the transition from single- toward multiple pulse for soliton fiber lasers
摘要： High-order soliton in anomalous-dispersion ultrafast fiber lasers is rarely researched due to its intrinsic instability in dissipative systems. For the first time, we numerically demonstrate the ultrafast pulse in fiber lasers will deviate from the fundamental soliton under strong pulse energy before splitting into multiple pulses. High-order soliton effect results in the single-pulse splitting into the dual-pulse. Sustaining switching between the single- and dual-pulse induced by the high-order soliton evolution and cross-gain-modulation was observed and analyzed. The results offer significant and novel insights for the soliton shaping dynamics and instability in anomalous-dispersion fiber lasers.
关键词： Mode-locked lasers,nonlinear fiber optics,temporal soliton and pulse propagation
更新于2025-09-16 10:30:52
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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) - Scrutinizing the Equidistance of Frequency Comb Sources
摘要： Frequency combs have revolutionized frequency metrology, enabling optical clockworks with unprecedended precisions approaching the 10-18 range. Early frequency comb measurements exclusively relied on mode-locked lasers, which provide a periodic waveform as a matter of working principle. In turn, the resulting frequency comb is guaranteed to be absolutely equidistant. While this expectation is ultimately based on theoretical mode-locking models, experimental tests have scrutinized deviations from equidistance of mode-locked laser combs down to the 10-15 level. Experimental tests of equidistance are rather elaborate and typically require beating of different spectral parts of the comb with a reference comb. Such tests have also been performed with microresonator combs, which are not a priori guaranteed to be equidistant from theoretical considerations. Finally, there are rather recent reports of quantum cascade laser combs; yet careful investigations of the equidistance of such sources still appear to be outstanding. Here we propose and demonstrate a novel experimental test for the equidistance of frequency combs.
关键词： metrology,frequency combs,mode-locked lasers,equidistance
更新于2025-09-16 10:30:52
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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) - Harmonic noise-like square pulse in an Er:Yb co-doped fiber laser at 1.61μm
摘要： The generation of high-power harmonic noise-like square pulses (NLSPs) is realized at 1.61 μm in an Er:Yb co-doped all-fiber mode-locked laser for the first time. By intra-cavity changing pump power and adjusting polarization state, the NLSP can operate in a fundamental or a high-order harmonic mode-locking (HML) state. The maximum average output power is about 1.26 W. To the best of our knowledge, this is the first demonstration of a watt-level harmonic NLSP.
关键词： noise-like pulse,Mode-locked lasers
更新于2025-09-16 10:30:52
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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) - Mode Re-Locking in an RF Detuned Actively Mode-Locked Fiber Ring Laser
摘要： RF detuning of the actively mode-locked ?ber ring laser (AMLL) causes deterioration in its performance due to lock-loss of higher cavity modes [1, 2]. The effects of detuning are typically mitigated by either modifying the cavity or using additional optical components [3]. We demonstrate an improvement in the performance of the detuned AMLL using multiple RF input signals without altering the cavity while achieving an extension of the injection range of the modes and increasing number of locked modes.
关键词： Lasers, injection-locked,Lasers, fiber,Laser theory,Mode-locked lasers
更新于2025-09-12 10:27:22
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Experimental exploration of mode-locking evolution mechanism in dual-ring fiber laser
摘要： We explored experimentally the mode-locking (ML) evolution mechanism of a dual-ring fiber laser. Increase of the total pump power up to 860 mW allowed the observation of the state changes from single-ring ML, dual-ring ML, to dual-ring self-starting ML. Moreover, a group of wave plates and a fixed polarization beam splitter were applied in each subring as precise attenuators. Rotation of each wave plate for an entire turn allowed the investigation of the ML evolution of the two subrings based on the intracavity power variation in each subring. The variation periodicity of the output power was analyzed for each subring and was found to be consistent with the theoretical results. Furthermore, the ML detachment threshold in each subring was estimated to explain the ML evolution. Our study provides a deeper understanding of the ML evolution in dual-ring fiber lasers and can aid their future optimal design for dual comb applications.
关键词： Fiber lasers,Mode-locking evolution,Cascaded nonlinear processes,Mode-locked lasers,Ultrafast mechanism
更新于2025-09-12 10:27:22
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Phase Noise Measurements and Performance of Lasers with Non-white FM Noise for Use in Digital Coherent Optical Systems
摘要： We measure the FM noise power spectral density of quantum-dot mode-locked lasers (QD-MLLs) and compare this to their measured linewidths as predictors of performance in a digital coherent system. We explain our observations in terms of the non-Lorentzian line shape of the source wherein linewidth is determined by the low frequency part of its FM noise. Investigation of system performance with simulations based on the measured phase sequences and back-to-back coherent transmission experiments, show that QD-MLLs with linewidths of several MHz can have comparable performance to that of a laser with only a few hundreds of kHz of Lorentzian linewidth, due to the non-white part of their FM noise. We show that spectral linewidths of lasers with similar spectral properties can underestimate their performance in coherent systems, regardless of the linewidth measurement technique used. We propose a “Lorentzian-equivalent linewidth” measure to characterize lasers with non-white FM noise and to estimate their impact in digital coherent optical systems. This measure is obtained from phase variations at frequencies higher than typical frequencies often used to characterize lasers with white FM noise, and comparable to the system baud. The proposed measure is shown to be a better predictor of system performance than the measured linewidth, for lasers with non-white FM noise. The impact of non-white FM noise on the optimization of carrier phase recovery and system performance is also discussed.
关键词： diode lasers,Coherent communication,optical fiber communication,mode-locked lasers
更新于2025-09-12 10:27:22
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Harmonic Mode-Locking in Bidirectional Domain-Wall Soliton Fiber Lasers
摘要： We report on the first experimental observation of passively harmonic mode-locking (HML) in a bidirectional domain-wall dark-soliton fiber laser. The domain-wall solitons (DWSs) are characterized, in which, the strong coupling between the two directions takes great responsibility for the generation. By appropriately altering the polarization state in the cavity, the stable fundamental domain-wall solitons and HML states could be obtained and switched with increasing the pump power. In our experiment, the repetition rate can be tunable from the fundamental mode locking of 2.96 MHz up to eighth-order HML of 23.68 MHz when the pump power is increased from 120 to 542.5 mW. Importantly, this HML operation of dark-pulse DWSs confirms that the DWSs are the intrinsic feature of the mode-locked lasers, as well as the conventional bright solitons. This work could provide a new perspective to the understanding of the formation and transformation of dark solitons, which may also find great potential applications in fiber sensing and future optical communication systems.
关键词： lasers and laser optics,mode-locked lasers,ultrafast photonics,pulse propagation and temporal solitons
更新于2025-09-12 10:27:22
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Generation of high-energy and low-repetition rate hybrid pulses from a passively mode-locked Tm-Ho co-doped laser
摘要： This study presents a passively mode-locked Tm-Ho co-doped ?ber laser at around 1840 nm with a low-repetition rate and high pulse energy. The laser delivers pulses at 93 kHz and produces a pulse energy of 18.5 nJ at 0.55 W pump power when the cavity length is 2.21 km. When the pump power is increased, high order of repetition rate outputs are observed. By a comparison of the spectra at various pump power levels indicates that the laser can be operated at hybrid multi-wavelength soliton mode-locking, depending on the pumping intensity. With the increase in pump power, single-wavelength soliton mode-locking and simultaneous of single- and dual-wavelength soliton mode locking are also observed. Besides, the system produces a laser at 1417 nm, which is induced by two-step absorption and the consequent stimulated emission. The low–repetition rate and high–pulse energy ?ber laser at around 1840 nm has potential applications in sensing, processing, and surgery research.
关键词： Optical ?ber lasers,Mode locked lasers,Ultrafast optics
更新于2025-09-12 10:27:22
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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) - A Multiple-Waveguide Mode-Locked Chip-Laser Architecture
摘要： Frequency combs and analogue to digital sampling are emerging applications that can benefit from advances in elegant, compact, and high performance miniature mode-locked lasers. By virtue of their ‘chip-scale’, and multiplicity of adjacent waveguides, compact cavity planar waveguide devices are suited to efficiently operate in the ~0.5 GHz to 10 GHz pulse regimes. The ultra-fast chip laser platform we have pioneered is based on direct inscription of sub-surface large mode-area waveguides into rare-earth doped fluorozirconate (ZBLAN) glass chips. Multiple waveguides per chip are rapidly written via computer numerically controlled (CNC) ultra-fast laser inscription (ULI); a flexible and advancing waveguide fabrication technique. The guided-wave confinement of these fiber like structures in this bulk gain media ensures efficient pump and cavity mode overlap, robust alignment, and single transverse mode operation. Our initial mode-locking experiments focused on erbium doped ZBLAN chips (sensitized by Yb). These lasers display reasonable cw laser performance, a large single transverse-mode, a wide tunable range covering 1510-1590 nm, and a zero-dispersion wavelength of 1650 nm, thereby reducing the requirement for dispersion compensation. The erbium ytterbium cerium co-doped ZBLAN chips have been demonstrated to produce transform limited mode-locked output near 1.55 μm, with pulse lengths down to 180 fs, and operation up to 3 GHz. In recent work we have also demonstrated cw mode-locking near 1 μm based on Yb doped ZBLAN chip lasers. This talk will provide an overview of chip fabrication, cavity design, mode-locking configuration, and mode-locking results we have achieved. By taking advantage of the multiple waveguide channels, we have demonstrated a cavity that could simultaneously operate adjacent mode-locked erbium lasers using all common cavity components. By slightly modifying one of the cavity lengths, the dual mode-locked laser was shown to operate as an ultra-stable dual frequency comb. This laser possessed the highest mutual coherence reported to date for a passively stabilised dual-comb laser.
关键词： waveguide,ZBLAN glass,frequency combs,ultra-fast laser inscription,mode-locked lasers
更新于2025-09-12 10:27:22
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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) - Nd,Gd:SrF <sub/>2</sub> Laser Generating 600 fs Pulses at 0.9 W of Pump Power
摘要： Fluoride crystals (CaF2, SrF2) doped with neodymium Nd3+ and codoped with non-active ions as Y3+, La3+, or Gd3+ for breaking clusters of active ions, have become recently interesting active media for the diode-pumped mode-locked lasers. They possess broader emission spectra as well as longer fluorescence lifetime in comparison with widely used crystals such as Nd:YAG or Nd:YVO4. The femtosecond Nd,Y:SrF2 laser generating 97 fs pulses was reported in the Ti:sapphire pumped system [1]. We have reported continuously mode-locked operation of this laser pumped by a 2 W multimode laser diode and mode-locked using a semiconductor saturable absorber generating pulses with the duration of 258 fs [2]. In laser systems with La3+ codoped crystals, which have wider tunability than Y3+ codoped crystals, passively mode-locked 354 to 1200 fs and continuous-wave 1044 to 1081 nm tunable operation was reported in the system pumped by 4 W laser diode [3]. Recently a new Nd,Gd:SrF2 crystal has been investigated and the dual wavelength mode-locked picosecond operation was reported for pump power higher than 3.8 W [4]. We reported femtosecond operation of laser with this crystal and obtained pulses as short as 228 fs with output power of 2 x 50 mW in system pumped by 2 W laser diode for absorbed pump power of 1320 mW [5]. In the present contribution we report on operation of this novel laser with a Brewster cut crystal in passively mode locked regime for extremely low pump power. Laser system schematic is similar as in ref. [5] and is shown in Fig. 1. A 5 mm long Brewster cut 0.5%Nd, 5%Gd:SrF2 crystal was pumped by a multimode 2 W laser diode at 796 nm and passively mode-locked using a semiconductor saturable absorber mirror (SAM). Using a chirped mirror M3 with GDD equal to -650 fs2 it was possible to achieve continuously mode locked regime at absorbed pump power of only 320 mW, with output power of 2 x 12 mW behind the mirror M4 in linearly polarized beams with nearly Gaussian spatial profile and pulse duration of 740 fs (assuming sech2 pulse shape). For higher absorbed pump power of 632 mW (905 mW incident on the crystal) the total output power of 2 x 20 mW was achieved with a pulse duration of 600 fs. The autocorrelation curve is shown in Fig. 2 together with the measured spectrum 3.3 nm wide, and centered at 1051.5 nm. The absorbed pump power is 2 - 4 times smaller in comparison with our previous results. The calculated time-bandwidth product of 0.536 gives potential to get shorter pulses (down to 352 fs) with optimum GVD compensation.
关键词： diode-pumped,semiconductor saturable absorber mirror,femtosecond pulses,Nd,Gd:SrF2,mode-locked lasers
更新于2025-09-12 10:27:22