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Carboxyl graphene oxide solution saturable absorber for femtosecond mode-locked erbium-doped fiber laser
摘要： The carboxyl-functionalized graphene oxide (GO-COOH) is a kind of unique two-dimensional (2D) material and possesses excellent nonlinear saturable absorption property and high water-solubility. In this paper, we prepare saturable absorber (SA) device by depositing GO-COOH nanosheets aqueous solution on a D-shaped ?ber. The modulation depth (MD) and saturable intensity of the SA are measured to be 9.6% and 19 MW/cm2, respectively. By inserting the SA into the erbium-doped ?ber (EDF) laser, a passively mode-locked EDF laser has been achieved with the spectrum center wavelength of 1562.76 nm. The pulse duration, repetition rate, and the signal-to-noise ratio (SNR) are 500 fs, 14.79 MHz, and 80 dB, respectively. The maximum average output power is measured to be 3.85 mW. These results indicate that the GO-COOH nanosheets SA can be used as a promising mode locker for the generation of ultrashort pulses.
关键词： nonlinear optical materials,mode-locked pulse,?ber lasers,carboxyl graphene oxide
更新于2025-11-28 14:24:03
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Switchable transverse-mode operation of an actively mode-locked EDF laser based on low-modal-crosstalk mode MUX/DEMUX
摘要： In this paper, we report an all-?ber actively mode-locked erbium-doped ?ber laser based on the mode multiplexer/demultiplexer (MUX/DEMUX). Higher-order mode and mode-locked pulse outputs can be realized simultaneously. The mode-locking is achieved by using a LiNbO3 Mach–Zehnder intensity modulator. Multiple linearly polarized (LP) modes in the ring ?ber laser are generated by mode MUX/DEMUX. For different spatial modes (LP01, LP11, LP21, hybrid modes), 17.32 ns, 20.40 ns, 23.00 ns and 17.24 ns mode-locked pulse trains are successfully obtained, respectively. The output laser operates at the fundamental frequency of 8.064 MHz with center wavelengths of 1528.71 nm for LP01 mode, 1528.30 nm for LP11 mode, 1530.45 nm for LP21 mode and 1530.05 nm for hybrid mode. Moreover, we also measure the slope ef?ciency, spectrum and intensity distribution. The results show that the proposed ?ber laser has potential applications in mode-division-multiplexed systems, optical sensing and optical ?ber communication.
关键词： Mode switching,Mode MUX/DEMUX,Mode-locked ?ber lasers
更新于2025-11-28 14:23:57
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TiOxNy Thin Film Sputtered on a Fiber Ball Lens as Saturable Absorber for Passive Q-Switched Generation of a Single-Tunable/Dual-Wavelength Er-Yb Double Clad Fiber Laser
摘要： The use of titanium oxynitride (TiOxNy) thin ?lms as a saturable absorber (SA) element for generation of passive Q-switched (PQS) laser pulses, from a linear cavity Er-Yb double-clad ?ber (EYDCF) laser, is demonstrated. Additionally, the deposition of the material as a thin ?lm covering a ?ber micro-ball lens (MBL) structure is reported for the ?rst time. The TiOxNy coating is deposited by a direct current (DC) magnetron-sputtering technique. The MBL is inserted within the laser cavity in a re?ection con?guration, alongside a re?ecting mirror. As a result, the coated ?ber MBL simultaneously acts as a SA element for PQS laser pulses generation and as an interference ?lter for wavelength selection and tuning of the generated laser line. Tunable single-laser emission in a wavelength range limited by dual-wavelength laser generation at 1541.96 and 1547.04 nm is obtained. PQS laser pulses with a repetition rate from 18.67 to 124.04 kHz, minimum pulse duration of 3.57 μs, maximum peak power of 0.359 W, and pulse energy of 1.28 μJ were obtained in a pump power range from 1 to 1.712 W.
关键词： Q-switched ?ber lasers,titanium oxynitride,DC magnetron sputtering,?ber micro-ball lens,saturable absorber materials
更新于2025-09-23 15:21:01
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Ultra-fast laser machining of stainless steel
摘要： Ultra-fast laser machining is emerging as an e?ective tool for modifying surface morphology in many technological ?elds. The process entails laser ablation, which in turn involves complex interplay between phenomena pertaining to laser matter interaction, thermo-physical effects, ionisation and material expansion, amongst others. In addition, the transient formation of surface plasmon polaritons and subsequent interaction with the impinging radiation can lead to quasi-periodic surface structures, in particular when metals or semiconductors are used. In the present paper, stainless steel is machined with the goal of producing smooth surfaces. Nonetheless, as demonstrated by highly sensitive scanning probe surface diagnostics, texturing is achieved at multiple length scales. Mechanisms leading to the observed surface features are proposed and the relationship with process parameters brie?y discussed.
关键词： Manufacturing,High-power ?ber lasers
更新于2025-09-19 17:13:59
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Wide-Span Multi-Wavelength High-Power Diode-Laser Pumping of Fiber Raman Laser
摘要： A multimode silica-core ?ber Raman laser was pumped directly by ?ve wavelength-combined multimode diode lasers. The pump wavelengths were spread over a bandwidth of ～700 cm?1, namely, at 976, 969, 950, 940, and 915 nm. This is larger than the Raman peak shift of 490 cm?1 . The output power reached 31.5 W with an overall slope ef?ciency of 42% at the wavelength of 1018 nm when pumped with the maximum launched power of 175 W. According to simulations, the ?ber was under-length and the output power could double in a longer ?ber. Our results suggest that pumping with spectrally combined diode lasers is a promising approach to high-power ?ber Raman lasers, even when the pump wavelengths are not optimized.
关键词： nonlinear optics,Raman lasers,Optical ?ber lasers
更新于2025-09-16 10:30:52
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Route from single-pulse to multi-pulse states in a mid-infrared soliton fiber laser
摘要： State-of-the-art ultrafast mid-IR ?ber lasers deliver optical solitons with durations of several hundred femtoseconds. The Er- or Ho-doped ?uoride gain ?bers generally used in these lasers have strong anomalous dispersion at ～3 μm, which generally forces them to operate in the soliton regime. Here we report that a pulse-energy clamping e?ect, caused by the buildup of intracavity nonlinearities, limits the shortest obtainable pulse durations in these mid-infrared soliton ?ber lasers. Excessive intra-cavity energy results in soliton instability, collapse and fragmentation into a variety of stable multi-pulse states, including phase-locked soliton molecules and harmonically mode-locked states. We report that the spectral evolution of the mid-IR laser pulses can be recorded between roundtrips through stretching their second-harmonic signal in a 25-km-length of single-mode ?ber. Using a modi?ed dispersive Fourier transform set-up, we were able to perform for the ?rst time spectro-temporal measurements of mid-IR laser pulses both in the pulsed state and during pulse collapse and fragmentation. The results provide insight into the complex nonlinear dynamics of mid-IR soliton ?ber lasers and open up new opportunities for obtaining a variety of stable multi-pulse mode-locked states at mid-IR wavelengths.
关键词： dispersive Fourier transform,soliton instability,multi-pulse states,pulse-energy clamping,mid-IR soliton ?ber lasers
更新于2025-09-16 10:30:52
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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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Mechanism of formation of noiselike pulses in passively mode-locked fiber lasers
摘要： We present the results of an analysis of noiselike pulses generated in passively mode-locked ?ber lasers with anomalous dispersion. The master equation used for the analysis takes into account the gain saturation, the quadratic frequency dispersion of the gain and the refractive index, and the cubic-quintic nonlinearity of the losses and refractive index. Reasons for the stabilization of noiselike pulses are investigated. It is found that the space-time localization of a noiselike pulse is associated with the suppression of single solitons located outside this pulse. The mechanism of such competition between single solitons and a noiselike pulse is determined.
关键词： noiselike pulses,passively mode-locked ?ber lasers,solitons,anomalous dispersion,nonlinear optics
更新于2025-09-12 10:27:22
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AlPO <sub/>4</sub> in Silica Glass Optical Fibers: Deduction of Additional Material Properties
摘要： A silica clad optical ?ber with a core comprised of SiO2, P2O5, Al2O3, and AlPO4 is analyzed in order to determine the impact of AlPO4 when added to silica. A chromatic dispersion curve is presented, from which the nonlinear refractive index is estimated to be similar to that of silica. When doped into SiO2, AlPO4 decreases the thermo-optic coef?cient (slightly), decreases the acoustic velocity, broadens the Brillouin spectral width through increased viscoelastic damping, and reduces the strength of the dependence of Brillouin frequency on temperature. Findings herein indicate that AlPO4 has a near-zero value of p12. It also is found that the ?ber does not have complete AlPO4 formation, with some P2O5 formation in Al2O3-rich regions of the ?ber. Given the relevance of AlPO4 to high power active ?ber technology, the presented data can be used for designing ?bers with enhanced performance characteristics, such as those with elevated threshold for the onset of stimulated Brillouin scattering.
关键词： Fiber optics,phosphorus,aluminum,?ber lasers,?ber nonlinear optics,optical materials,optical ?ber testing,glass
更新于2025-09-11 14:15:04
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Splitting and Motions of Dissipative Soliton Resonance Pulses in Mode-Locked Fiber Lasers
摘要： We numerically investigated the splitting and motions of dissipative soliton resonance (DSR) pulses in an all-normal-dispersion Yb-doped ?ber laser mode-locked by a non-linear optical loop mirror. At certain values of the system parameters, the initial single Gaussian pulse can evolve into an unstable DSR pulse with several dark solitons inside. After collisions of dark solitons, a big intensity dip occurs at the center of the DSR pulse, leading to the splitting of the DSR pulse. After splitting, the peak-to-peak separation between two DSR pulses increases at ?rst and ?nally reaches a ?xed value of 193 ps, indicating a steady-state multipulse operation The relative motions of separated DSR pulse originate from the phase shift.
关键词： dissipative soliton resonance,pulse splitting,non-linear optics,?ber lasers,mode-locked lasers
更新于2025-09-11 14:15:04