增益模块长高比对输出功率和提取效率的影响

为了得到HF化学激光器的增益发生器较佳的模块尺寸,研究了增益模块长高比对输出功率及放大级提取效率的影响。使用基于变换坐标系的有限差分方法,计算了主振荡功率放大器（MOPA）结构HF激光器不同增益模块长高比条件下的主振荡器输出功率、放大级提取效率及经放大后的输出功率。计算结果表明:对于MOPA结构HF激光器而言,当增益体积一定、小信号增益曲线相同时,随着增益模块长高比的减小,主振荡器输出功率和经放大级放大后的输出功率将有所增加,但放大级的能量提取效率将降低;当增益模块长高比已经较小(小于５)时,进一步降低长高比对激光器输出功率和放大级提取效率的影响微弱。     

增益模块长高比对输出功率和提取效率的影响

为了得到HF化学激光器的增益发生器较佳的模块尺寸,研究了增益模块长高比对输出功率及放大级提取效率的影响。使用基于变换坐标系的有限差分方法,计算了主振荡功率放大器（MOPA）结构HF激光器不同增益模块长高比条件下的主振荡器输出功率、放大级提取效率及经放大后的输出功率。计算结果表明：对于MOPA结构HF激光器而言,当增益体积一定、小信号增益曲线相同时,随着增益模块长高比的减小,主振荡器输出功率和经放大级放大后的输出功率将有所增加,但放大级的能量提取效率将降低;当增益模块长高比已经较小(小于５)时,进一步降低长高比对激光器输出功率和放大级提取效率的影响微弱。     

主振荡功率放大短脉冲光纤激光系统的偏振特性研究

对自行研制的主振荡功率放大结构短脉冲双包层光纤激光系统(2W,30ps)的偏振特性进行了研究.分别研究了种子源激光和经过包层泵浦放大后输出激光在连续工作和脉冲输出情况下的偏振特性,结果表明在不加偏振控制措施情况下,系统输出为椭圆偏振光,偏振度和偏振角都容易受到光纤扰动的影响;在激光腔内加入起偏器后,输出线偏振光,偏振态相对比较稳定,但是偏振角度仍然容易受到光纤扰动的影响.实验证明:经过高功率放大后,输出激光的偏振态稳定性有一定程度的下降,在进行激光相干合成前需进一步加以控制.     

1 mJ, 500 kHz Nd:YAG/Nd:YVO<Subscript>4</Subscript> MOPA laser with a Nd:YAG cavity-dumping seed laser

We report a high-repetition-rate, high-pulse-energy master oscillator power amplifier (MOPA) laser system, in which the seed laser from the Nd:YAG rod-based oscillator cavity dumped at 500 kHz, was scaled up consecutively by a four-stage Nd:YVO₄ preamplifier and a two-stage Nd:YAG zigzag slab main amplifier. The laser pulsed output with the average power of 510 W was achieved, with the efficiency extraction of 26.6% at the main amplifier stage and the single-pulse energy of 1.02 mJ.     

90.4-W all-fiber single-frequency polarization-maintained 1083-nm MOPA laser employing ring-cavity single-frequency seed oscillator

A high-power all-fiber single-frequency polarization-maintained（PM）laser operating at 1 083 nm is demonstrated using a master oscillator power amplifier（MOPA）structure.The seed source of this MOPA laser system is an in-house-built ring-cavity fiber oscillator.Four-stage amplification configuration is employed, in which the maximal output power of the main amplifier is 90.4 W,corresponding to a conversion efficiency of 72.5%.The polarization extinction ratio of the output light is 13 dB.The amplified spontaneous emission is suppressed by a factor of over 25 dB,and no stimulated Brillouin scattering effect is observed when a large-mode-area and high absorption coefficient PM gain fiber is employed.     

Coherent combination of high-power, zigzag slab lasers

We demonstrate a scalable architecture for a high-power, high-brightness, solid-state laser based on coherent combinations of master oscillator power amplifier chains. A common master oscillator injects a sequence of multikilowatt Nd:YAG zigzag slab amplifiers. Adaptive optics correct the wavefront of each amplified beamlet. The beamlets are tiled side by side and actively phase locked to form a single output beam. The laser produces 19 kW with beam quality <2x diffraction limited. To the best of our knowledge, this is the brightest cw solid-state laser demonstrated to date.     

High power high beam quality diode-pumped 1319-nm Nd:YAG oscillator-amplifier laser system

This paper demonstrated a high power and high beam quality diode-pumped 1319-nm Nd:YAG master oscillator-power amplifier laser system. A thermally near-unstable resonator with four-rod birefringence compensation flat--flat cavity was adopted as the master oscillator. A solid etalon was inserted in the unidirectional ring resonator to compress the laser linewidth. Under a repetition rate of 500~Hz and pulse width of 160~\mus, the master oscillator delivers an average output power of 16.8~W at 1319~nm with linear polarisation, beam quality factor M^{2} = 1.16 and linewidth of 3.2~GHz. A double-pass power amplifier with two amplifier stages was employed for higher power scaling and the output power was amplified to be 25.9~W with M^{2} = 1.43.     

输出平均功率大于2W的高功率、包层抽运、超短脉冲铒镱共掺光纤激光器

采用主振荡功率放大的方式，研制成功集宽带波长连续可调谐、带宽内输出功率谱均衡、高重复频率和高功率性能于一体的超短脉冲包层抽运铒镱共掺光纤激光器.将优化主振荡器和功率放大器的腔结构与掺铒光纤的饱和增益特性结合起来，实现了1535nm—1570nm(35nm带宽)的输出功率均衡的波长连续可调谐激光输出，在带宽内激光功率的最大波动仅为0.5dBm；带宽内平均输出功率大于2W、脉冲重复频率大于10GHz、脉冲宽度小于30ps.该激光器具有综合性能指标先进、结构简单、全光纤化、使用方便等优点. 关键词： 光纤激光器 包层抽运 短脉冲 高重复频率     

Single-frequency, single-mode, plane-polarized ytterbium-doped fiber master oscillator power amplifier source with 264 W of output power

We present a single-frequency, single-mode, plane-polarized ytterbium-doped all-fiber master oscillator power amplifier source at 1060 nm generating 264 W of continuous-wave output power. The final-stage amplifier operated with a high gain of 19 dB and a high conversion efficiency of 68%. There was no evidence of rollover from stimulated Brillouin scattering even at the highest output power, and the maximum output was limited only by the available pump power.     

An Efficient Single-Frequency Yb-Doped All-Fiber MOPA Laser at 1064.3 nm

An efficient narrow-linewidth single-frequency(SF) Yb-doped all-fiber master oscillator power amplifier(MOPA)laser operating at 1064.3 nm is demonstrated experimentally.A ring cavity SF fiber laser is used as the seed source for the MOPA system and the Yb-doped fibers are employed as the gain medium or the saturable absorber.The SF operation is observed to be stable without mode hopping.The highest output power of 266 mW is obtained under the 400 mW pump power with the corresponding slope efficiency of 66.2%.The linewidth of the amplified output laser is approximately 1 kHz and its optical signal-to-noise ratio is over 45 dB.     

侧面泵浦主振荡功率放大器中的光束质量提高

报道了一种利用球差补偿效应提高侧面泵浦主振荡功率放大器输出光束质量的实验装置。在理论上提出了一种新的球差补偿方法,利用正球差经过会聚透镜焦点后向负球差转化的现象,补偿下一放大级中的正球差效应。在实验上搭建了两级放大的侧面泵浦Nd:YAG主振荡功率放大器。在连续输出的情况下,从振荡级输出功率为42W、光束质量因子为1.48的种子光,经过一级放大后的功率为74W,光束质量因子恶化为1.80;继续经过二级放大后,光束质量因子提高为1.40。实验结果表明,所提出的球差补偿理论是提高激光放大过程中光束质量的有效手段。     

侧面泵浦主振荡功率放大器中的光束质量提高

报道了一种利用球差补偿效应提高侧面泵浦主振荡功率放大器输出光束质量的实验装置。在理论上提出了一种新的球差补偿方法,利用正球差经过会聚透镜焦点后向负球差转化的现象,补偿下一放大级中的正球差效应。在实验上搭建了两级放大的侧面泵浦Nd:YAG主振荡功率放大器。在连续输出的情况下,从振荡级输出功率为42 W、光束质量因子为1.48的种子光,经过一级放大后的功率为74 W,光束质量因子恶化为1.80;继续经过二级放大后,光束质量因子提高为1.40。实验结果表明,所提出的球差补偿理论是提高激光放大过程中光束质量的有效手段。     

Theory of Pr:ZBLAN ultraviolet upconversion fiber master oscillator power amplifier

A theoretical study for ultraviolet upconversion fiber master oscillator power amplifier (MOPA) based on the transition from the 4f5d state to the ³H₄ ground state in Pr³⁺:ZBLAN fiber is performed by using steady population rate equations and propagation equations. The variation of the output power with the fiber length of master oscillator and MOPA and the launched pump powers, the dependence of the slope efficiency on the fiber length of master oscillator and MOPA, and the optimum fiber length of MOPA as a function of the launched pump powers, are calculated. Both the output power and the slope efficiency of MOPA are 2-3 times those of the simplex oscillator. It is found that the UV upconversion fiber MOPA system can effectively improve the output power and the slope efficiency of laser.     

High-power continuous-wave output of master oscillator power amplifier system at 1053 and 1083 nm

We report the efficient generation of high-power laser radiation at 1053 and 1083 nm wavelength by using of a hybrid master oscillator fiber power amplifier system, consisting of a diode-pumped Yb-doped oxyorthosilicate solid state laser as the master oscillator and an Yb-doped large-mode-area fiber as the power amplifier. Efficient tunable diode-pumped Yb-doped oxyorthosilicate lasers at 1053 and 1083 nm have been constructed, which was scaled up to a maximum output power of 34.5 W at 1053 nm and 30.2 W at 1083 nm by a fiber power amplifier, corresponding to a slope efficiency of 93.9 and 87.8%, respectively.     

Flashlamp-pumped Nd:KGW laser in MOPA configuration: comparative study of several rods

The laser performance of the Nd:KGW crystal has been studied in a master oscillator and power amplifier configuration (MOPA). Several crystals from two different producers were investigated for the oscillator and the amplifier. A maximum single-pass gain of 25 was observed in free-running and Q-switched mode. We obtained a maximum output amplified energy of 400 mJ at 30 Hz (with a pulse duration of 10 to 30 ns) with a divergence less than 3 mrad. We also studied the limitations of this configuration due to the very high gain of the Nd:KGW crystal. Received: 21 September 1998 / Revised version: 10 January 1999 / Published online: 19 May 1999     

Femtosecond pulse generation and amplification in Yb-doped fibre oscillator-amplifier system

In recent times ytterbium (Yb) doped fibre-based mode-locked master oscillator and power amplifier have attracted a great deal of interest because of their inherent advantages like flexibility, reliability, compactness, high power handling capability and diffraction limited output beam quality as compared to the solid-state counterpart. But, to successfully develope of high-power femtosecond oscillator-amplifier system based on Ybdoped fibre, an appropriate choice of the mode-locking regime and the amplifier geometry are required. Development of an all-fibre integrated high-power Yb-doped fibre oscillator-amplifier system in which the advantages of a fibre-based system can be fully exploited remained a challenge as it requires the careful optimization of dispersion, nonlinearity, gain and ASE contribution.     

Diode-pumped 250-W zigzag slab Nd:YAG oscillator amplifier system

A laser-diode-pumped zigzag slab Nd:YAG master oscillator power amplifier (MOPA) system featuring high pulse energy and high average power was developed for pumping of an ultrashort-pulse laser system. The MOPA system consists of an oscillator, a preamplifier, two postamplifiers, and image-relay telescopes. The postamplifiers have an angle-multiplexed ring-type double-pass configuration. A pulse energy of 1.26 J and an average power of 251 W were obtained at a repetition rate of 200 Hz. The frequency-doubled power when a LiB(3)O(5) crystal was used was 105 W at a repetition rate of 170 Hz. The intensity profiles of the fundamental and the second harmonic are nearly top-hat shaped and are suitable for pumping.     

1.8 mJ高倍率Nd:YAG板条皮秒激光放大器

设计了一种高倍率的固体皮秒脉冲激光放大器,采用Nd:YAG板条作为激光增益介质。借助板条结构的角度选通结构,搭建了板条五通放大系统,实现了对注入皮秒脉冲激光的高倍率放大。种子源工作在脉冲模式,放大器泵浦源在连续模式工作。皮秒光纤激光器可以在不同的重复频率下工作,脉冲宽度为13.4 ps。种子光经过隔离和耦合系统之后,注入板条的单脉冲能量为25 nJ。当种子源工作重复频率为24.46 MHz时,板条放大器输出平均功率377 W,单脉冲能量15.5 μJ;当种子源工作重复频率为49.8 kHz时,板条放大器输出平均功率89 W,单脉冲能量1.8 mJ,峰值功率为134 MW,放大倍率达到7.2×104。     

Injection-Seeded 500 Hz Repetition Rate High Peak Power Single-Frequency Nd:YAG Laser for Mid-Infrared Generation

We develop an injection-seeded single-frequency neodymium-doped yttrium aluminum garnet (Nd:YAG) laser with 500 Hz repetition rate and high peak power. The laser construction is designed as seed injection and master oscillator power amplifier (MOPA) including single-frequency master oscillator, extra-cavity frequency doubling crystal, and round-trip power amplifier. The master oscillator can emit 1,064 nm laser of 8.4 mJ with 6.8 ns pulse width at the pump energy equal to 23 mJ. A green laser energy of 1.1 mJ is obtained by setting the proper temperature of the LBO crystal. The pulse energy of 1,064 nm laser decreases to 6.5 mJ after passing through the LBO crystal and rises to 25.3 mJ after a round-trip power amplifier corresponding to the extraction efficiency of 29%. The final output pulse width is 6.5 ns, representing a peak power of 3.9 MW. The 1,064 nm laser beam quality factor M² of the master oscillator and the amplified one are 1.3 and 1.5, respectively. The laser will be used to generate mid-infrared where the 532 nm laser with narrow pulse width is to pump sheet optical parametric oscillator (OPO) and the 1,064 nm laser with high peak power to pump the OPO.     

基于简单MOPA结构实现3.08 kW全光纤窄线宽线偏振激光输出

基于简单的主振荡功率放大结构,演示了一种高功率窄线宽线性偏振全光纤激光器,其最大输出功率为3.08 kW,3 dB线宽为0.2 nm。在整个功率缩放过程中,偏振消光比约为94%,光束质量M ²约为1.4。这是国内外首次实现3 kW全保偏光纤激光输出,与基于相位调制的窄线宽激光器相比,该激光器可实现近似的线宽,同时具有受激布里渊散射阈值高、系统结构简单、成本低等特点。