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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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Passively Q-switched and mode-locked Tm-Ho co-doped fiber laser using a WS2 saturable absorber fabricated by chemical vapor deposition
摘要： We demonstrate a passively Q-switched and mode-locked Tm-Ho co-doped fiber laser based on a WS2 saturable absorber (SA) fabricated by chemical vapor deposition method. When the pump power increases from 0.32 W to 0.38 W, the repetition rate of the Q-switched laser pulse increases 47.1 kHz to 90.1 kHz and the pulse width decreases from 6.2 μs to 1.7 μs. In addition, the mode-locking operation can also be observed by adjusting the polarization controller (PC) and mode-locked laser pulses at 1883.2 nm can be achieved at a high pump power between 0.5 W and 0.64 W. The pulse duration is 1.07 ns and repetition rate is 23.8 MHz and the pulse is the longest mode-locked pulse with WS2-SA ever reported.
关键词： Mode-locked lasers,Optical fiber lasers,Ultrafast optics
更新于2025-11-28 14:24:03
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Alternated Q-switched and gain-switched dual-pulse Yb fiber laser with Tm-Ho co-doped fiber as saturable absorber
摘要： We demonstrate a dual-wavelength and dual-pulse Yb-doped fiber laser with a Tm-Ho co-doped fiber as saturable absorber (SA). The wavelength of the first pulse in the dual-pulsing output is at 1064 nm generated via SA-induced self Q-switching and the second pulse is at 2127.7 nm and generated by gain-switching with the laser at 1064 nm as the pump for the Tm ions in the Tm-Ho co-doped fiber and thus induced stimulated emission. With the increases of the pump power, the pulse duration of the two pulses is decreased depending on the level of the pump. The pulse duration of the laser at 1064 nm decreases from 1.4 μs to 296 ns when the pump power increases from 275 mW to 475 mW, while the pulse duration at 2127.7 nm is reduced from 440 ns to 246 ns when the pump increases from 300 mW to 475 mW. Accordingly, the repetition rate is decreased from 17.4 kHz to 6.8 kHz. The experimental result shows that Tm-Ho co-doped fiber is an excellent candidate for SA-induced Q-switching at 1064 nm.
关键词： Q-switched lasers,Optical fiber lasers,Ultrafast optics
更新于2025-11-28 14:24:03
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High-power, high-spectral-purity GaSb-based laterally coupled distributed feedback lasers with metal gratings emitting at 2? <i> <b>μ</b> </i> m
摘要： We report on the fabrication of high-power, high-spectral-purity GaSb-based laterally coupled distributed feedback (LC-DFB) lasers emitting at 2 μm. Second-order Chromium-Bragg-gratings are fabricated alongside the ridge waveguide by lift off. Due to the introduction of gain coupling, the lasers exhibit a stable single mode operation [side-mode suppression ratio (SMSR) >40 dB] from 10 °C to 50 °C and the maximum SMSR is as high as 53 dB. At a heat-sink temperature of 10 °C, the lasers emit more than 40 mW continuous-wave in a single longitudinal mode. A high external quantum efficiency of 48% is obtained, resulting in a notable increase in power conversion efficiency peaking at 13%. The lasers achieve a comparable output power with that of the index-coupled LC-DFB lasers, while maintaining a better single mode performance. Thus, we prove the feasibility of the metal-grating LC-DFB structure to achieve high-power, frequency-stable semiconductor lasers through a simpler and much more convenient way.
关键词： metal gratings,high-spectral-purity,high-power,distributed feedback lasers,GaSb-based lasers
更新于2025-11-28 14:24:03
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High-power single-longitudinal-mode double-tapered gain-coupled distributed feedback semiconductor lasers based on periodic anodes defined by i-line lithography
摘要： In this paper, we demonstrate a regrowth-free double-tapered gain-coupled distributed feedback semiconductor laser. It is designed based on periodic surface current injection to reach a high-power and single-longitudinal mode. A continuous-wave output power of over 1.2 W/facet is achieved at 4 A. High single-longitudinal-mode output power reaches up to 0.9 W/facet at 3 A at each uncoated facet. The side mode suppression ratio is nearly 30 dB at 980 nm. The 3 dB spectral width is less than 2.7 pm. The lateral far field divergence angle is only 14.5 °, the beam quality factor M2 is 1.7, achieving a near-diffraction-limit emission. Our device, produced by standard i-line lithography, enhances the output power while obtaining the pleasurable spectral and spatial properties. It has great potential in widespread commercial applications such as high efficiency pumping sources for its low-cost, easy fabrication technique and excellent performance.
关键词： Double-tapered,Distributed feedback lasers,Gain-coupled,Semiconductor lasers
更新于2025-11-28 14:24:03
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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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High Power 1.5 μm Broad Area Laser Diodes Wavelength Stabilized by Surface Gratings
摘要： Wavelength stabilization against temperature variation of high-power broad area 1.5-μm InGaAsP/InP laser diodes is demonstrated by employing surface gratings. The development targets application in eye-safe automotive LIDAR systems, which would bene?t from deploying narrowband receiver ?lters to block ambient solar radiation for improved signal-to-noise ratio. The surface grating is monolithically integrated on the laser chip using nanoimprint lithography. The peak power of the lasers exceeded 6 W in pulsed mode, for an FWHM spectral width of 0.3 nm and a peak wavelength drift of only 0.1 nm/°C. The wavelength shift with temperature is reduced by ?ve times compared to broad area high-power Fabry–Perot laser diodes typically employed in LIDAR systems.
关键词： high power,distributed Bragg re?ector,LIDAR,Diode lasers
更新于2025-11-28 14:24:03
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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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Pulse-diode-intermittent-pumped 2-μm acousto-optically Q-switched Tm:YAG laser
摘要： An innovative pulse-diode-intermittent-pumped 2-micron acousto-optically Q-switched Tm:YAG laser is presented for the first time, which can improve the output energy, while ensuring the operation repetition of laser. Maximum output energy of 6.83 mJ and minimum pulse width of 367.7 ns at Q-switched repetition rate of 200 Hz is obtained at pump energy of 86.2 mJ. The output wavelength is 2014.9 nm. The beam quality factor Mx2 is 1.59. The stability is larger than 98%.
关键词： Q-switch,Diode-pumped lasers,Tm:YAG
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