Yb∶Y_2O_3陶瓷薄片激光器获得10.5 W连续激光输出

室温下采用中心波长约970 nm准直输出的大功率激光二极管模块作为抽运源,端面抽运双程吸收的腔型结构,抽运原子数分数为8%的Yb:Y2O3多晶透明陶瓷片获得连续激光输出。抽运阈值功率为7 W,当抽运功率达到35 W时,获得优化连续激光输出功率为10.5 W,光光转换效率为30%,斜率效率为37.5%。激光输出功率随抽运功率基本呈线性增长。采用更高功率抽运源、优化谐振腔结构和减小热效应的影响,Yb∶Y2O3陶瓷激光器的输出功率和效率将会得到进一步提高。     

Low-power-pumped high-efficiency frequency doubling at 397.5 nm in a ring cavity

We report low pump power high-efficiency frequency doubling of a fundamental laser beam at 795 nm, corresponding to the rubidium D1 line, to generate UV light at 397.5 nm using a periodically poled KTi OPO4（PPKTP） crystal in a ring cavity. We obtain maximum stable output power of 49 m W for mode-matching pump power of 110 m W, corresponding to 45% raw efficiency（56% net efficiency when considering the output coupling mirror’s 80% transmission）. This is the highest efficiency obtained at this wavelength in PPKTP with such low pump power. We obtain 80% beam coupling efficiency to single-mode fiber, demonstrating high beam quality.     

Pump slope-improved fiber-ring laser by recycling the residual pumping power

We investigate an improvement in the pump slope efficiency for an erbium-doped fiber-ring laser. The method is based on the residual pump power reused by means of a fiber mirror. Under the conditions of a 4-m erbium-doped fiber (EDF), 10 mW of pump power, and a 99% reflectivity of a fiber-Bragg grating, the pump slope efficiency may reach 19.70% compared to 15.37% for a conventional fiber-ring laser. The maximum lasing power is increased from 14.6 to 18.7 mW corresponding to a 1.07-dB lasing power enhancement. The side-mode suppression ratio is as high as 67.6 dB with a line width of less than 0.05 nm.     

双后向结构的线宽拓展L波段超荧光光源

报道了采用两级级联双后向抽运的光源结构,实现高效率和线宽拓展的L波段掺铒光纤超荧光光源.通过数值模拟,研究了两级光纤长度分配和抽运功率比例对光源输出特性的影响.模拟表明,该结构可获得线宽拓展的平坦L波段光谱,相比常规L波段光谱线宽拓展了15 nm,达近60 nm.此外,抽运功率比例为1∶1时该结构的抽运转换效率最高.利...     

Efficient Tm:YLF laser with a volume Bragg grating recycle pumped by laser diode

By using a pump recycling configuration, we presented a high efficient diode-pumped Tm:YLF laser with a volume Bragg grating. When the incident pump power was 33.1 W, a maximum output power of 11.1 W at 1907.8 nm with full width at half maximum of 0.6 nm was obtained. The slope efficiency with respect to the incident pump power was 44.8%, and the optical-to-optical efficiency was 33.5%. In addition, the VBG-based Tm:YLF laser was employed as a pumping source of Ho:YAG laser, the maximum output power of 4.7 W with a slope efficiency of 67.0% was obtained, corresponding to Tm-to-Ho conversion efficiency of 51.6%.     

采用国产大模场面积双包层光纤的714W连续光纤激光器

采用两个中心波长约976 nm准直输出的高功率半导体激光模块为抽运源,通过空间滤波和非球面透镜耦合技术,双端抽运长度为21 m的大模场面积国产掺镱双包层光纤,获得了714.5 W的高功率连续激光输出。采用反向抽运,当入纤抽运功率为760 W时,激光输出功率达到501 W;采用双端抽运,当入纤抽运功率为1137 W时,获得了714.5 W的高功率连续输出,光光转换效率为62.8%,斜率效率为67%。     

High efficiency and high output power fiber-optic parametric amplifier

A highly efficient fiber-optic parametric amplifier (FOPA) is presented. A nearly complete pump depletion of 99.92% in a single-pumped FOPA is experimentally demonstrated with a pump power of 1W. In addition, a high signal output power of 0.53W is presented, corresponding to a power conversion efficiency of 53%, which is believed to be the highest efficiency ever reported for an FOPA.     

Highly efficient CW intracavity frequency-doubled Yb:YAG-LBO laser at 515 nm under 968 nm diode laser pumping

We describe the output performances of the 1030 nm transition in Yb:YAG under in-band pumping with diode laser at the 968 nm wavelength. An end-pumped Yb:YAG crystal yielded 1.93 W of continuous-wave (CW) output power for 9.1 W of absorbed pump power. The slope efficiency with respect to the absorbed pump power was 23.6%. Furthermore, 205 mW 515 nm green light was acquired by frequency doubling, resulting in an optical-to-optical efficiency with respect to the absorbed pump power of 2.7%. Comparative results obtained for the pump with diode laser at 940 nm are given in order to prove the advantages of the in-band pumping.     

20 W passively cooled single-mode all-fiber laser at 2.8 μm

A maximum output power of 20.6 W at 2.825 μm from an erbium-doped all-fiber laser is reported, which we believe is the highest output power for this laser transition in single-mode operation. The slope efficiency of the passively cooled laser was up to 35.4% with respect to the absorbed pump power. Accounting for an estimated round-trip intracavity loss of 1.3 dB, we calculated a theoretical conversion efficiency of 39.5%, which is 15% higher than the Stokes efficiency of 34.3%. We believe this is the first experimental confirmation of the predicted pump energy recycling for this fiber laser. The narrow laser linewidth varied from 0.09 to 0.16 nm from low to maximum output power.     

Experimental study on kilowatt fiber laser in an all-fiber configuration

A high-power fiber laser in an all-fiber format is reported. The system consists of 36 pump ports, which use both counter and forward pump configuration. In the experiment, 1 008-W output power is obtained when 24 pump ports are used with a total pump power of 1477 W. The optical-to-optical conversion efficiency is 68% and the 3-dB bandwidth of laser output increases with output power. Presently, the output power is only limited by the pump source. It can be predicted that the laser power can be further scaled if more pump sources are utilized.     

Characteristics of Cladding-Pumped Short Er3+/Yb3+ Codoped Single Mode Phosphate Glass Fibre

We experimentally investigate the laser characteristics of a series of short pieces of newly-developed Er³⁺/Yb³⁺ codoped single mode phosphate glass fibres via the cladding pump of a 976nm multimode laser diode. A stablecontinuous-wave single transverse mode laser with over 85mW at 1553nm is generated from a 5.5-cm-long active fibre. Single mode laser output power per unit length is up to 15mW/cm. Moreover, the slope efficiency is 11.8% when the pump power is below 940mW and the 3dB linewidth is 0.06nm at the maximum pump power. The numerical simulation results show that the laser emission slope efficiency can exceed 20% by means of increasing the coupling efficiency of the pump to the fibre core further.     

End-pumped Nd:YAG zigzag slab laser with weak pump absorption

A diode-pumped Nd：YAG oscillator laser with an end-pumped zigzag slab architecture and weak pump absorption is developed. An output power of 253 W with a slope efficiency of 50.2% and an optical-optical conversion efficiency of 39.6% is achieved from the resonator, which emits the maximum power of 290 W with 840-W pump power. An optimum laser diode （LD） array coolant temperature is chosen in an attempt to realize the weak but uniform pump absorption. of zigzag slab resonator depends sensitively on the Furthermore, we have confirmed that the performance incident angle of the beam at the slab end face.     

A Low-Pump-Threshold Photonic Crystal Fibre Raman Laser

We investigate a photonic crystal fibre Raman laser using fibre Bragg grating pairs as cavity mirrors. The threshold pump power is up to 0.65 W by decreasing the cavity loss and using a photonic crystal fibre with high Raman gain coefficient. A maximum continuous-wave output power of 2. 7 W is obtained at the maximum incident pump power of 5.6 W. The corresponding optical conversion efficiency and the slope efficiency are about 48% and 56%, respectively.     

Efficient 1061 and 1329 nm laser emission of Nd:CNGG lasers under 885 nm diode pumping into the emitting level

We report an efficiency Nd:CNGG laser operating at 1061 and 1329 nm, respectively, direct pumped by a diode laser at 885 nm for the first time to our knowledge. The maximum outputs of 4.5 and 2.9 W, at 1061 and 1329 nm, respectively, are obtained in a 6-mm-thick 0.5 at % Nd:CNGG crystal with 13.5 W of absorbed pump power at 885 nm, leading to a high slope efficiency with respect to the absorbed pump power of 32.2 and 22.1%. Under traditional pumping at 808 nm, the maximum outputs of 3.9 and 2.7 W, at 1061 and 1329 nm, respectively, are obtained with 15.4 W of absorbed pump power, corresponding to the slope efficiency with respect to the absorbed pump power of 25.2 and 17.9%.     

高功率光纤激光器二级抽运技术的理论分析

从理论上分析了高功率光纤激光器直接抽运和二级抽运的斜率效率和热管理问题. 计算结果表明:波长为975 nm的激光直接抽运产生波长为1070 nm的激光时,理论斜率效率为80%,但当抽运光功率为10 kW时,在强制水冷条件下纤芯极值温度也难以降到150 ℃以下;在二级抽运技术中,波长为1018 nm的激光抽运产生波长为1070 nm的激光时,若采用传统的包层抽运技术,其斜率效率不足20%,如果抽运功率填充因子由0.0025提高到0.1,则理论上斜率效率可由18.5%提高到80.9%,从而总斜率效率由15.5 关键词： 二级抽运 功率填充因子 斜率效率 热管理     

All-Solid-State Nd:YAG Laser Operating at 1064nm and 1319nm under 885nm Thermally Boosted Pumping

We report a high-effciency Nd：YAG laser operating at 1064 nm and 1319nm, respectively, thermally boosted pumped by an all-solid-state Q-switched Ti：sapphire laser at 885 nm. The maximum outputs of 825.4 m W and 459.4mW, at 1064nm and 1319nm respectively, are obtained in a 8-ram-thick 1.1 at.% Nd：YAG crystal with 2.1 W of incident pump power at 885nm, leading to a high slope efficiency with respect to the absorbed pump power of 68.5% and 42.0%. Comparative results obtained by the traditional pumping at 808nm are presented, showing that the slope efficiency and the threshold with respect to the absorbed pump power at 1064nm under the 885nm pumping are 12.2% higher and 7.3% lower than those of 808rim pumping. At 1319nm, the slope efficiency and the threshold with respect to the absorbed pump power under 885nm pumping are 9.9% higher and 3.5% lower than those of 808 nm pumping. The heat generation operating at 1064 nm and 1319 nm is reduced by 19.8% and 11.1%, respectively.     

Highly efficient cascaded P-doped Raman fiber laser pumped by Nd:YVO4 solid-state laser

A highly efficient cascaded P-doped Raman fiber laser （RFL） pumped by a 1064-nm continuous wave （CW） Nd：YVO4 solid-state laser is reported. 1.15-W CW output power at 1484 nm is obtained while the input pump power is 4 W, corresponding to the power conversion efficiency of 28.8%. The threshold pump power for the second-order Stokes radiation is 1.13 W. The slope efficiency is as high as 42.6%. The experimental results are in good agreement with theoretical ones. Furthermore, the power instability of the P-doped RFL at 1484 nm in an hour is observed to be less than 5%.     

Highly efficient continuous-wave composite Nd:YAG laser at 1,112 nm under diode pumping directly into the emitting level

We present an efficient, high-brightness laser at 1,112 nm by combining the direct pumping technique with an 885 nm laser diode and the composite crystal. Output power as high as 12.8 W at 1,112 nm is achieved under 22.2 W of absorbed pump power and it yields an optical-to-optical efficiency of 57.7 % and a slope efficiency of 64.0 % with respect to the absorbed pump power. To the best of our knowledge, both of these optical-to-optical and slope efficiencies with respect to the absorbed pump power are the highest values ever reported for 1,112 nm Nd:YAG lasers. Modeling of the temperature rise and stress induced in the laser crystals, with and without the undoped cap, and employing the pump at 808 and 885 nm are performed, respectively. Contributions of the composite crystal geometry and of the pump at 885 nm to lowering the threshold power, enhancing the optical-to-optical and the slope efficiencies with respect to the absorbed pump power are discussed, respectively.     

Optimization of erbium-doped fiber MOPA laser

An erbium-doped fiber laser (EDFL) constructed in a master oscillator and power amplifier (MOPA) configuration is analyzed. The pump powers for the fiber cavity laser and the booster amplifier stages are managed properly to achieve maximal pump conversion efficiency. Our design achieves a pump conversion efficiency of 91.4%, corresponding to a quantum efficiency of 96.6%, for a 1565.8 nm MOPA laser pumped by a total power of 300 mW at 1480 nm. The optimized MOPA laser shows a 25% enhancement in the pump conversion efficiency, compared to a non-MOPA fiber laser. A side lobe suppression ratio of 48 dB for the optimized MOPA laser is observed.     

掺Yb3+双包层光纤激光器的数值分析

 对掺Yb³⁺双包层光纤激光器不同参数情况下的输出功率和增益分布进行了数值模拟，分析了一端泵浦和双端泵浦方式下输出特性的差异，激光沿光纤长度方向的分布，输出功率与光纤长度、腔镜反射率及泵浦功率的关系。结果显示：两端泵浦较一端泵浦增益更加平坦，输出功率也稍高；当泵浦光波长为975nm时，输出激光功率对光纤长度更为敏感，最佳光纤长度相对于泵浦光波长为915nm时短且转化效率高；在大功率长光纤的情况下，光纤有损耗时输出功率随输出腔镜反射率的增加单调地减小，无损耗时输出功率不随输出腔镜反射率变化。