20 W all fiber supercontinuum generation from picosecond MOPA pumped photonic crystal fiber

An all fiber high power supercontinuum (SC) source is demonstrated by pumping a section of photonic crystal fiber (PCF) with a picosecond MOPA laser. The core of the PCF is enlarged at the input end through a serious of PCF post processing method to match the output fiber of the picosecond laser, to ensure low loss splicing, hence high power operation of the whole system. The supercontinuum output spectrum covers the wavelength range from 650 nm to beyond 1700 nm. Limited by available pump power, 20 W super-continuum output power is obtained under 29.5 W picosecond pump power, giving a high optical to optical conversion efficiency of 67.8%.     

888 nm LD抽运Nd∶YVO4被动锁模皮秒振荡器

报道了基于888 nm半导体抽运Nd∶YVO4晶体连续被动锁模的皮秒振荡器。通过热激发抽运方式改善激光器的热性能,提高锁模振荡器输出的平均功率与单脉冲能量。利用半导体可饱和吸收体(SESAM)实现激光器锁模运转的启动与维持。在抽运功率为60 W时,获得最大输出功率为15 W,重复频率为53 MHz的皮秒脉冲输出,光-光转换效率为24%。在输出功率为15 W时脉冲宽度为45 ps。     

高功率全光纤保偏主振荡功率放大型光纤激光器的实验研究

进行了全光纤保偏主振荡功率放大型光纤激光器的实验研究. 采用两级级联放大的方式, 利用纤芯为5 μupm 的小芯径双包层保偏光纤, 在最大抽运功率为88 W 时实现了67 W的1083 nm保偏激光输出, 纤芯内的激光功率密度约为3.4 W/μupm², 光-光转换效率为76%．分析结果表明, 进一步提高抽运功率有望获得更高功率的激光输出．     

光纤激光泵浦MgO:PPLN高功率中波红外光参量振荡器

为实现高效率、高功率中波红外激光输出,研制基于MgO:PPLN晶体的中波红外光参量振荡器（OPO）,泵浦源为基于主振荡功率放大（MOPA）结构的线偏振掺Yb光纤激光器（YDFL）。实验结果表明:YDFL可实现最高79.1 W的1064.1 nm脉冲线偏振激光输出;在YDFL泵浦下,通过优化输出镜曲率半径和泵浦光束腰直径,该OPO实现最高9.15 W的3.754 μm脉冲激光输出,光光转换效率为11.57%,重复频率为300 kHz,脉冲宽度约为110 ns。     

高功率,红光至中红外可调谐腔内和频光学参量振荡器

本文利用高重复频率,高平均功率大模场面积飞秒光纤激光器作为同步抽运源,抽运以多周期极化掺氧化镁铌酸锂为非线性晶体的单共振光学参量振荡器,获得了高功率可调谐红光至中红外光,信号光调谐范围为1450—2200 nm,闲频光调谐范围为2250—4000 nm,在2 W的抽运功率下,信号光输出波长为1502 nm时获得最大输出功率374 mW,转换效率为18.7%,脉冲宽度为144 fs,此时中红外输出中心波长为3.4μm,平均功率为166 mW.再利用BBO晶体对信号光进行腔内和频,获得和频光输出波长调谐范围为610—668 nm,在4.1 W抽运的情况下,最高平均功率为615 nm处的694 mW,转换效率达16.9%.     

国产大功率全光纤主振荡功率放大器

 以国产掺Yb光纤为增益介质,利用国产泵浦源和光纤器件,构建了主振荡功率放大结构的全国产大功率全光纤激光器。在注入的最大泵浦功率为75 W时,获得了52.5 W,1 080 nm激光的稳定输出,光-光效率为70%。实验结果表明,提高泵浦功率可获得更高的输出功率。     

国产全光纤结构激光器实现245 W高功率激光输出

 以国产掺镱光纤为增益介质,利用国产泵浦源和光纤器件,构建了主振荡功率放大（MOPA）结构的全国产大功率全光纤激光器。激光器包括10 W种子激光器和高功率放大器两部分。在注入最大泵浦功率为356 W时,获得了245 W波长1 080 nm激光的稳定输出,光-光效率为69%。激光器单次连续出光时间约30 min,功率稳定性在1%以内。目前激光器输出功率受限于泵浦功率,增加泵浦源的数目有望进一步提高输出功率。     

Efficient, high-power, ytterbium-fiber-laser-pumped picosecond optical parametric oscillator

We report a high-power picosecond optical parametric oscillator (OPO) synchronously pumped by a Yb fiber laser at 1.064 μm, providing 11.7 W of total average power in the near to mid-IR at 73% extraction efficiency. The OPO, based on a 50 mm MgO:PPLN crystal, is pumped by 20.8 ps pulses at 81.1 MHz and can simultaneously deliver 7.1 W of signal at 1.56 μm and 4.6 W of idler at 3.33 μm for 16 W of pump power. The oscillator has a threshold of 740 mW, with maximum signal power of 7.4 W at 1.47 μm and idler power of 4.9 W at 3.08 μm at slope efficiencies of 51% and 31%, respectively. Wavelength coverage across 1.43-1.63 μm (signal) and 4.16-3.06 μm (idler) is obtained, with a total power of ~11 W and an extraction efficiency of ~68%, with pump depletion of ~78% maintained over most of the tuning range. The signal and idler output have a single-mode spatial profile and a peak-to-peak power stability of ±1.8% and ±2.9% over 1 h at the highest power, respectively. A signal pulse duration of 17.3 ps with a clean single-peak spectrum results in a time-bandwidth product of ~1.72, more than four times below the input pump pulses.     

Interferometric output coupling of ring optical oscillators

We demonstrate the successful deployment of an antiresonant ring (ARR) interferometer within a ring optical resonator and its use for absolute optimization of output power. The integration of the ARR interferometer in a folded arm of the ring oscillator provides continuously variable output coupling over broad spectral range and under any operating conditions. We demonstrate the technique using a picosecond optical parametric oscillator (OPO), where we show continuously adjustable output coupling and optimization of the output power for different pump power conditions, from 3.5 W to 13.5 W. By operating the OPO under an optimized output coupling at 14 W of pump power, we obtain >5 W of extracted signal power, more than 2.6 times that with a ~5% conventional output coupler. We also show that the inclusion of the ARR interferometer has no detrimental effect on the spatial, temporal, and spectral characteristics of OPO output.     

22 W single mode tm-doped fiber MOPA in all-fiber format

We demonstrate an all-fiberized laser in main oscillator power amplification (MOPA) configuration with 22 W output power and a central wavelength of 1950 nm. The laser is pumped by pigtailed laser diode with a central wavelength of 793 nm. Strictly single-mode can be obtained and the optical to optical efficiency of the fiber laser is 40% with respect to the pump power. No power-roll is observed and the power can be scaled straightforwardly by using more pump sources.     

分布式抽运连续光纤激光器研究

为了避免高功率光纤激光器中光纤端面出现热效应问题,依据多点级联结构的耦合器,对分布式抽运的光纤激光器进行了研究。首先,介绍了实验室自主研制的级联耦合器。然后,分析了耦合器插入对光纤激光器的影响。最后,选用自制的耦合器搭建了分布式抽运的光纤激光器。实验结果表明:对耦合器插入损耗的研究,能够促进高功率级联耦合器的实现。在光纤激光器结构中,975 nm泵浦功率注入1.1 k W时,1 080nm激光功率输出为770 W,光-光转换效率为77%。在主控振荡功率放大结构中,激光功率输出为635 W,放大级的光-光转换效率为78%。分布式抽运方式可以使泵浦光多点注入,避免了热量的集中,能够获得千瓦级的激光功率输出。     

High-power Tm~(3+)-doped all-fiber laser operating at1908 nm by a master oscillator power amplifier configuration with narrow spectral linewidth

We demonstrate a diode-pump Tm~(3+)t-doped all-fiber laser operating at 1908 nm based on a master oscillator power amplifier(MOPA) configuration. In our work, 152 W of laser output power is generated by a total incident pump power of 434 W at 790 nm, corresponding to the total optical efficiency of 35%. The laser wavelength is1908.29 nm. To the best of our knowledge, it is the highest output power reached around 1908 nm with such a narrow linewidth of 0.18 nm based on a MOPA configuration.     

Efficient continuous-wave eye-safe region signal output from intra-cavity singly resonant optical parametric oscillator

We report an efficient continuous-wave (CW) tunable intra-cavity singly resonant optical parametric oscillator based on the multi-period periodically poled lithium niobate and using a laser diode (LD) end-pumped CW 1064 nm Nd:YVO₄ laser as the pump source. A highly efficiency CW operation is realized through a careful cavity design for mode matching and thermal stability. The signal tuning range is 1401-1500 nm obtained by varying the domain period. The maximum output power of 2.2 W at 1500 nm is obtained with a 17.1 W 808 nm LD power and the corresponding conversion efficiency is 12.9%.     

Continuous wave,singly resonant MgO:PPLN OPO pumped by a Nd:YVO<Subscript>4</Subscript>/YVO<Subscript>4</Subscript> ring laser

A continuous wave (CW), extra-cavity singly resonant optical parametric oscillator (SRO) has been demonstrated. The SRO is based on 5% magnesium-oxide doped periodically-poled lithium niobate (MgO:PPLN) pumped by a CW Nd:YVO₄/YVO₄ ring laser centered at 1064.4 nm. The nonlinear crystal temperature is kept at 120.0 ± 0.1°C and a domain period of 30 μm is used in this experiment. When the pump power is 11 W, an output power of 2.0 W at the idler wavelength of 3.479 μm has been obtained from the OPO. The optical-optical conversion efficiency is about 18.2%, and the slope efficiency is about 20.8%.     

An efficient intracavity-pumped KTP optical parametric oscillator at 1572 nm

We demonstrate an efficient and eye-safe wavelength intracavity optical parametric oscillator (OPO),based on a KTP crystal inside a Q-switched Nd:YVO4 laser end pumped by a fiber-coupled diode laser. Inthe acousto-optic Q-switched operation with the pulse repetition rate of 10 kHz, a 1572-nm eye-safe laser with the average power of 237 mW at the incident pump power of 5.64 W is obtained. Under the pulse repetition rate of 5 kHz, the signal light with pulse width of 2 ns and peak power of 18.5 kW is achieved.The conversion efficiency of the average power is 4.2% from pump diode to OPO signal output and thesignal pulse duration is about 13 times shorter than that of the depleted pump light.     

准相位匹配PPMgLN光参量振荡技术

 理论上分析了PPMgLN光参量振荡波长调谐特性，计算了泵浦阈值和转换效率。准相位匹配情况下，周期调谐是获得中红外波长调谐有效方法之一。采用高斯光束泵浦，当泵浦功率密度超过阈值泵浦功率密度约6.5倍时，可以获得最高转换效率，约71%。采用1 064 nm激光泵浦多周期PPMgLN晶体，实验上获得了波长调谐范围2.7~4.8 mm，当泵浦功率为8 W时，在波长3.7 mm处激光输出功率超过1.6 W，斜效率超过20%，相应的转换效率约为69%，与理论分析基本一致。     

All fiber MOPA laser-pumped,continuous-wave,mid-infrared,singly-resonant optical parametric oscillator based on periodically poled MgO-Doped LiNbO<Subscript>3</Subscript>

We report a continuous-wave (CW) mid-infrared singly resonant optical parametric oscillator (SRO) based on periodically poled MgO-doped LiNbO₃ (PPMgLN) pumped by a high power, single frequency fiber laser in master oscillator-power amplifier (MOPA) configuration at 1.064 μm. Using four-mirror ring OPO cavities, at the PPMgLN’s grating period of 30.5 μm and the temperature of 23°C, we achieved the maximum idler output power of 7.2 W at 3.4 μm when the pump power was 52.8 W. The total power-conversion efficiency from the pump to the idler in this experiment is about 13.6%, and corresponds to ∼44% of quantum-limited performance.     

A High Conversion Efficiency Q-Switched Intracavity Nd:YVO_4/KTA Optical Parametric Oscillator under Direct Diode Pumping at 880nm

We report a high conversion efficiency Q-switched Nd:YVO_4/KTiOAsO_4(KTA) intracavity optical parametric oscillator(IOPO) operating near 3.5 um based on direct 880 nm laser diode(LD) pumping. A maximum average idler output power of 2.6 W with a pulse width of about 7.9 ns is achieved under an absorbed LD power of 45.4 W at a pulse repetition rate(PRR) of 10 kHz. The maximum optical-optical conversion efficiency from LD power to OPO mid-infrared(MIR) output of 6.74% is achieved. To our knowledge, this is the highest conversion efficiency for a KTA-IOPO by exploiting a Q-switched laser as the parent fundamental pump source. The beam quality factors M~2 of the MIR beam at the full output power with a PRR of 10 kHz are within 2.12 in both the horizontal and vertical directions, indicating a near Gaussian mode.     

Direct-liquid-cooled Nd:YAG thin disk laser oscillator

A Nd:YAG thin disk laser oscillator convection-cooled directly by the liquid is demonstrated. Lasing performance at different flow patterns and different flow rates is studied in detail. Micro-scale eddies that appear at the disk edge can induce decrease of the output power and the degradation of beam quality. 17.1 W of output power is realized at the maximum pump power of 54.8 W, corresponding to the optical–optical efficiency of 31.2 %, and the slope efficiency of 37.5 %.     

高功率高重频U型腔激光器的仿真与实验研究

 为了得到结构紧凑的高功率、高重复频率固体激光器,设计了“U”型光学谐振腔,并利用LAS-CAD软件分析了激光晶体的热效应和激光输出特性。根据仿真结果进行了具体实验,最终得到了腔长400 mm的紧凑型固体激光器。在重复频率为100 kHz,泵浦功率为60 W时,输出功率达到21.6 W,光-光转换效率为36%,斜率效率为39.9%。