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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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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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Ultrahigh resolution spectroscopy for dimethyl sulfide at the ??1- and ??8-bands by a distributed feedback interband cascade laser
摘要： The ultrahigh-resolution, air-broadened mid-infrared absorption spectrum of dimethyl sulfide (DMS) was recorded in the spectral region of 2994.17–2999.03 cm?1, where the strong ν1-/ν8-bands are located. Benefitting from the tunable laser absorption spectrometry with a distributed feedback interband cascade laser, the spectral resolution achieved 5.69 × 10?6 cm?1. The recorded spectra of DMS are very close to that in the Pacific Northwest National Laboratory (PNNL) database, however it has a much lower absorbance uncertainty of 0.38%. And the maximum relative difference of the full width at half maximum and the integrated area of spectral peaks between the recorded spectra and the PNNL data are as large as 16.7% and 27.9%, respectively, which could mainly come from the difference of the spectral resolution. The more accurate reference spectrum is hopeful to be applied to absolute measurement and remote sensing for gaseous DMS.
关键词： Tunable laser absorption spectroscopy (TLAS),Dimethyl sulfide (DMS),Ultrahigh-resolution spectrum,Interband cascade laser (ICL),Mid-infrared
更新于2025-09-23 15:19:57
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m thulium fiber laser with all-fiber ring cavity
摘要： A 1.7-μm thulium-doped all-fiber laser based on a ring-cavity configuration is demonstrated. The long-wavelength lasing near the 1.9-μm thulium emission peak was suppressed using a wavelength division multiplexer and single-mode–multimode–single-mode (SMS) fiber device, both of which served as a short-pass filter instead of the grating devices usually used in 1.7-μm thulium fiber lasers. A stable hundred-milliwatt-level 1720-nm laser output with a narrow spectral linewidth on the order of gigahertz was obtained after the optimization of the output coupling, active fiber length, and SMS device. With a cascaded SMS filter, the output power was further scaled to 227 mW under a launched 1570-nm pump power of 2.8 W, while the slope efficiency was 10.3%. The wavelength coverage could be further extended by using different SMS devices and applying tension on them.
关键词： short-pass filter,1.7 μm,ring cavity
更新于2025-09-16 10:30:52
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Direct Generation of a Laguerre-Gaussian-Mode Optical Vortex Beam in a Single-Frequency Nd:YVO4 Unidirectional Ring Laser
摘要： A single-frequency, unidirectional ring laser with a ?rst order Laguerre-Gaussian (LG01) mode output end-pumped by using a ring-shaped pump beam is reported. This approach has been applied to a diode-pumped Nd:YVO4 laser in a traveling wave resonator con?guration yielding 2.1 W and 1.5 W of single-frequency LG01 mode outputs with helical wavefronts of left- and right-handedness, respectively. Moreover, we show that its wavefront helicity can be switched by changing the lasing direction and frequency. The selection mechanism of the wavefront helicity and the prospects of this approach are discussed.
关键词： Diode-pumped solid state lasers,Single-frequency laser,Optical vortices,Laguerre-Gaussian mode
更新于2025-09-11 14:15:04
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Measurements of spectroscopic parameters of CO2 transitions for Voigt, Rautian, Galatry and speed-dependent Voigt profiles near 1.43 μm using the WM-DAS method
摘要： Linestrengths, self-broadening and narrowing coefficients for 8 absorption transitions of CO2 near 1.43 μm were measured using the wavelength modulation direct absorption spectroscopy (WM-DAS) at 300-1000 K and 5-20 kPa. The SNR was enhanced to 1500 for the peak absorbance around 5% at room temperature and remains at 550 for the peak absorbance around 1% at high temperatures by use of the WM-DAS method. The Voigt, Rautian, Galatry and quadratic speed-dependent Voigt profiles were used to recover the absorbance and retrieve the best-fit spectroscopic parameters and their temperature dependence. The quadratic speed-dependent Voigt profile was found to give the best combination of accuracy and robust lineshape parameters. The measured linestrengths and self-broadening coefficients compare well with the available values listed in the HITRAN/HITEMP database. The self-narrowing coefficients were also determined for GP, RP and qSDVP with analyses of the uncertainties in these spectroscopic parameters.
关键词： WM-DAS method,Galatry profile,speed-dependent Voigt profile,Voigt profile,spectroscopic parameters,Rautian profile,CO2
更新于2025-09-10 09:29:36