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Passively Q-switched fiber laser tunable by Sagnac interferometer operation
摘要： In this paper, a stable passively Q-switched Erbium-doped fiber laser (EDFL) tunable by Sagnac interferometer operation was described by using a graphene oxide saturable absorber (SA) as a Q-switcher. The wavelength operation of the Q-switched EDFL was tunable from 1566.3 nm to 1559.3 nm by increasing the temperature of sagnac loop mirror (SLM) from 30 °C to 70 °C in the figure-of-eight laser configuration. At 1566.3 nm operation, by increasing the pump from the threshold power of 77.3 mW to 126.5 mW, the repetition rate can be increased from 30.7 kHz to 41.5 kHz while the pulse width was narrowed from 10.2 to 7.3 μs. The Q-switching threshold pump power increased with the increase of the temperature, which then shifted the operation to a shorter wavelength. However, the laser efficiency increased at a shorter wavelength operation. At 1561.4 nm operation, the maximum pulse energy of 20.5 nJ was obtained at 161.0 mW pump power.
关键词： Q-switching operation,Fiber lasers,Sagnac loop mirror,Temperature tuning
更新于2025-11-28 14:24:03
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70?nm, broadly tunable passively Q-switched thulium-doped fiber laser with few-layer Mo0.8W0.2S2 saturable absorber
摘要： In this work, a thin Mo0.8W0.2S2 film is proposed and fabricated for the use as a saturable absorber (SA) in a thulium-doped fiber laser (TDFL) cavity. The few-layer Mo0.8W0.2S2 nanoparticles are obtained through hydrothermal exfoliation as a thin film and suspended in a polymer host, which is then placed between two fiber ferrules to serve as an SA. The proposed laser is capable of generating outputs with a maximum repetition rate of 65.79 kHz and a minimum pulse width of 1.84 μs at the maximum pump power of 168.92 mW, as well as pulse energies and peak powers as high as 35.73 nJ and 13.92 mW. The laser also has a broad tuning output from 1927.2 nm to 1996.8 nm, giving a tuning band of about 70 nm. The generated pulses are stable with a signal-to-noise ratio of 50.0 dB. The proposed laser has a high potential for operation near the 2000 nm wavelength region, with multiple bio-medical and sensing applications.
关键词： Thulium,Molybdenum compounds,Q-switching lasers
更新于2025-11-28 14:24:03
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Switchable and dual-wavelength self-Q-switched fiber laser based on a homemade Er/Yb double clad fiber and polarization maintaining fiber Bragg grating
摘要： We report an experimental study on the self-Q-switched operation of a linear cavity fiber laser based on a homemade Er/Yb double clad fiber as gain medium. The parameters of the self-Q-switched pulses depend on the active fiber length of 2, 3, and 4 m. With a maximum fiber length of 4 m, stable self-Q-switched pulses are obtained for the whole 976 nm pump range, with a minimum pulse duration of 1.24 μs and a maximum repetition rate of 92.57 kHz. When the fiber length is shortened to 2 m, the range of the pump power level, at which the self-Q-switched operation is attained, is significantly diminished. Besides, dual-wavelength and switchable single-wavelength laser operations of the fiber laser are achieved by using a polarization maintaining fiber Bragg grating as spectral filter. Laser wavelengths at 1536.7 and 1537.1 nm with a line-width of 0.4 nm are obtained. The maximum average output power for the Q-switched laser operating in the dual-wavelength regime is 472 mW.
关键词： self-Q-switching,fibre lasers,Er/Yb double-clad fiber lasers
更新于2025-11-28 14:24:03
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An All-Optical, Actively Q-Switched Fiber Laser by an Antimonene-Based Optical Modulator
摘要： Q-switched ?ber lasers are of great interest in industrial material processing, nonlinear frequency conversion, spectroscopy etc. However, passive Q-switching possesses drawbacks of degradation and failure of the saturable absorber and the di?culty in accurate modi?cation of the repetition rate. To overcome these issues, active Q-switching that can normally modulate the cavity quality-factor by an externally-driven Q-switcher is in high demand. Herein, an actively Q-switched laser with antimonene-based all-optical modulator is devised based on the high photo-thermal e?ciency (48%) and broadband response in antimonene. It is demonstrated that this actively modulated laser represents all-optically tunable output parameters (e.g., output repetition rate), environmental stability, and easy synchronization. It is anticipated that this actively antimonene-based all-optical modulator with advantages of large modulation depth, low energy consumption, and high conversion e?ciency has great potential in all-optical information processing and pulsed laser engineering.
关键词： actively Q-switching,antimonene,2D materials,all-optical modulators
更新于2025-11-28 14:24:03
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Pure gold saturable absorber for generating Q-switching pulses at 2?μm in Thulium-doped fiber laser cavity
摘要： We experimentally demonstrate Q-switched Thulium-doped fiber laser operating at 1949.19 nm using pure gold saturable absorber (Au-SA) as a Q-switcher. The Au-SA was fabricated by depositing gold particles molecules using electron beam evaporation on the surface of a polyvinyl alcohol (PVA) film. Subsequently, stable Q-switched pulses were obtained within the 1552 nm pump power range from 343.1 to 467.3 mW, with repetition rate tuned from 11.7 kHz to 21.95 kHz. At 467.3 mW pump power, the TDFL produced pulses train with the pulse width of 2.6 μs and the maximum pulse energy of 89.8 nJ. These results propose that pure gold could be a promising saturable absorber for pulse generation in 2 μm wavelength region.
关键词： Thulium-doped fiber laser,Q-switching,Pure gold saturable absorber
更新于2025-11-28 14:24:03
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Passively Q-switched erbium-doped fiber laser using quantum dots CdSe embedded in polymer film as saturable absorber
摘要： We demonstrate a passively Q-switched erbium doped fiber laser (EDFL) based on quantum dots (QD) CdSe as a saturable absorber (SA). The synthesized CdSe powder was embedded into a poly(methyl methacrylate) (PMMA) using emulsion polymerization process. The film is sandwiched between two fiber connector via an adapter to form a fiber-compatible SA device. By integrating the SA device into the EDFL ring cavity, the stable Q-switched operation is achieved at 1559.35 nm as the pump power is varied within 30–118 mW. The laser has a pump threshold of 20.4 mW. The pulse repetition rate shows an increasing trend from 33.2 to 68.45 kHz, whereas the pulse width exhibits a decreasing trend from 10.04 to 4.30 μs as the pump power is increased from 30 to 118 mW. The highest pulse energy of 11.83 nJ is obtained at a pump power of 118 mW. These results indicate that QD CdSe is a promising SA for Q-switching laser operation.
关键词： Q-switching,Quantum dots CdSe,Saturable absorber
更新于2025-11-28 14:23:57
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Spatial-mode switchable, multi-wavelength all-fiber erbium-doped fiber (EDF) laser based on low modal crosstalk mode multiplexer/demultiplexer (MUX/DEMUX)
摘要： We experimentally demonstrate an all-fiber erbium-doped fiber ring laser based on a Sagnac interferometer with a low modal crosstalk mode multiplexer/demultiplexer (MUX/DEMUX). Three linearly polarized (LP) modes are generated by mode MUX/DEMUX, which consists of cascaded mode-selective couplers. The proposed fiber laser can simultaneously achieve spatial-mode switching and multi-wavelength tuning. In the experiment, single-, dual-, and triple-wavelength lasing outputs for LP01, LP11, LP21 and hybrid modes are obtained. The stabilities for LP01, LP11, LP21 and hybrid modes are investigated in more than 20 min, 16 min, 12 min and 16 min, respectively. Moreover, the mode intensity profiles, the OSNRs of the lasing output and the slope efficiencies are also measured.
关键词： multi-wavelength fiber laser,mode multiplexer/demultiplexer (MUX/DEMUX),spatial-mode switching,Sagnac interferometer
更新于2025-11-28 14:23:57
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Molybdenum tungsten disulphide (MoWS <sub/>2</sub> ) as a saturable absorber for a passively Q-switched thulium/holmium-codoped fibre laser
摘要： In this work, a passively Q-switched Thulium/Holmium-doped fibre laser (THDFL) using a molybdenum tungsten disulphide (MoWS2) saturable absorber (SA) is proposed and demonstrated. The MoWS2 nanosheets are prepared by hydrothermal exfoliation and then suspended in a polyvinyl alcohol (PVA) thin film host. Q-switching of the THDFL at a maximum 1550 nm pump power of 445.2 mW gives a maximum repetition rate and minimum pulse width of 36.3 kHz and 2.8 μs with a corresponding pulse energy of 86.4 nJ and peak power of 31.1 mW. The MoWS2 based Q-switched THDFL’s output has a very high signal-to-noise value of ～ 62.2 dB which strongly indicates that the laser is working in a stable operation. To the best of our knowledge, this is the first demonstration of MoWS2 as a passive SA in a THDFL for operation in the 2.0 μm region. The proposed laser would have significant medical and sensing applications, particularly at the biologically active 2.0–2.1 μm regions.
关键词： thulium/holmium-doped fibre,transition metal dichalcogenides,Saturable absorber,Q-switching
更新于2025-11-28 14:23:57
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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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Unraveling the electrical properties of solution-processed copper iodide thin films for CuI/n-Si solar cells
摘要： The effects of temperature and liquid-phase iodination on the electrical property of spin coated CuI thin films have been investigated in details. The XRD study indicates that CuI thin films are polycrystalline in nature and I-doping enhances the crystal quality and size of the films. The SEM images show that the surface uniformity of the CuI thin films increases due to I-doping. The doping of iodine increases the conductivity as well as carrier concentration and mobility of the films as confirmed by Hall study. The temperature dependent resistivity of CuI film shows a sharp fall of resistivity at ~80 °C for un-doped films whereas this behavior disappears for I-doped films. The optical transmittance and band gap of the I-doped films also increases indicating high degeneracy of the films. These findings imply that I-doped spin coated CuI thin films are potential candidate for the solution-processed CuI/n-Si solar cells.
关键词： liquid-phase I-doped,spin coat,CuI thin films,switching-behavior,electrical properties
更新于2025-11-21 11:18:25