Multi-coupler side-pumped Yb-doped double-clad fibre laser and pump light leakage at coupler

A multi-coupler side-pumped Yb-doped double-clad fibre laser with output power of 1.38 W and slope efficiency of 48.9% by the fibre angle-polished method is demonstrated. Its pump light leakage at the fibre coupler is also investigated experimentally and theoretically.     

双包层掺Yb3+纤激光器的脉动现象及分析

对掺yb 3 双包层光纤激光器的输入输出特性进行了实验研究.实验中发现当泵浦功率略超过阈值后,光纤输出功率开始变得不稳定,在一定范围内反复上下波动,并有明显的周期性,即出现所谓"自脉动"行为.利用可饱和吸收体模型对作用的具体过程给出了一种新的解释.     

高功率光纤激光器及其应用

掺镱双包层光纤激光器是国际上近年来发展的一种新型固体激光器,它具有光束质量好、体积紧凑、效率高等优点.介绍了高功率掺镱双包层光纤激光器的原理特点、发展现状及其应用前景.可以预计这种新型激光器必将逐步取代传统激光器.     

掺镱双包层光纤激光器热应力场的理论研究

针对高功率掺镱双包层光纤激光器(DCFL)的热应力模型,对影响热应力场分布、包层表面最大热应力的参数如:纤芯半径、泵浦方式、泵浦吸收系数进行了研究.结果表明,热破坏作用主要集中于纤芯和包层表面;减小纤芯半径或增加光纤长度能够降低包层表面的最大热应力值;双端对称泵浦较之其它泵浦方式性能更优;采用非均匀泵浦吸收系数方案在降低包层表面最大热应力的同时,维持了高功率输出.     

掺Yb3+双包层光纤激光器的研究进展

光纤激光器以其独特的优势得到快速发展,其应用范围已经扩展到工业加工、国防军事、医疗等领域。综述了连续、脉冲掺Yb3+双包层光纤激光器的国内外研究进展,介绍了利用能承受高功率的合束器、光纤光栅的全光纤激光器,利用种子光主振荡光纤放大技术产生高光束质量、高平均功率、高峰值功率的脉冲光纤激光器。分析了影响光纤激光器功率提高的因素,如光纤的损伤、非线性性效应、热效应。最后,对掺Yb3+双包层光纤激光器的发展前景进行了展望。     

高功率掺镱双包层光纤激光器热效应理论研究

针对高功率双包层光纤激光器热效应严重制约着光纤激光器的输出功率和光束质量这一现象,利用热传导方程和边界条件推导出了双包层光纤激光器温度分布的解析解,进而分析了热效应引起的应力分布,温度和应力引起的折射率变化以及热效应引起的光程差。结果表明,在纤芯轴线处切向、法向、轴向应力分别达到负的最小值,而在光纤表面处径向应力为0,法向、轴向达到正的最大值;应力引起的折射率变化与温度引起的折射率变化相比较小;温度变化是热效应引起光程差主要原因,热膨胀和热应力引起的光程差较小。     

掺镱双包层光纤激光器多波长输出性能分析

从理论上分析了由F-P滤波器实现的多波长双包层光纤激光器(DCFL)的边界条件和输出功率,在考虑了F-P滤波器中双色镜反射率的波长依赖关系的前提下,对影响多波长输出功率和消光比的参数如双色镜和光纤出光端面的反射率、抽运功率等进行了研究。结果表明,光纤出光端面的反射率存在一个最佳值,再配合适当的双色镜反射率,能使多波长输出的功率和消光比达到很好的均衡。适当增大抽运功率也能优化多波长输出功率和消光比。通过控制F-P滤波器的腔长,能够调节多波长输出的数目。     

大模场面积掺镱双包层光纤的色散测量

大模场面积掺镱双包层光纤的色散特性在高功率超连续谱的产生中具有重要影响。搭建了一套基于马赫-曾德尔干涉仪和超连续谱光源的超宽波段、高精度的色散测量系统。干涉仪的测量臂插入待测光纤,参考臂通过高精度步进电机调节光程。通过此系统,仅使用27.2 cm长的样品对大模场面积掺镱双包层光纤的色散特性进行了精确测量。实验记录了700~1 600 nm范围内不同波长的干涉条纹,计算得到光纤的色散曲线。使用全矢量有限元法对光纤的色散进行了数值模拟,模拟结果与实验结果一致,证明了实验方法与系统的精确性。     

1 W single-transverse-mode Yb-doped double-clad fibre laser at 978nm

A novel all-glass Yb-doped double-clad fibre laser that emits over 1 W of single-transverse-mode output at 978 nm is described. This device is efficiently pumped with 2.5 W of launched power from a single 200 μm broad-area laser diode at 915 nm     

Generation of bound states of three ultrashort pulses with a passively mode-locked high-power Yb-doped double-clad fiber laser

We report the generation of high-power ultrashort bound states of three pulses in an ytterbium-doped double-clad fiber laser. The laser is mode-locked through nonlinear polarization rotation technique in a unidirectional cavity configuration. A pair of diffraction grating is incorporated in the cavity to compensate for the normal dispersion of the fiber. The laser generates chirped bound states of three pulses with either equal or different time separations, with more than 500-pJ energy per pulse. These pulses are subsequently compressed to 100 fs with a compression factor of more than 40.     

高功率光纤激光器用20/400双包层掺镱光纤

采用改进化学气相沉积结合溶液掺杂法制造出了掺镱石英光纤预制棒,预制棒轴向上芯径波动小于5%,折射率差波动小于8%。研磨加工后拉制出20/400双包层掺镱光纤,光纤纤芯不圆度为2%,芯包同心度偏差为0.87 μm。双包层掺镱光纤在1095 nm的包层损耗为2.1 dB/km。采用拉制的掺镱双包层光纤作为直接振荡结构全光纤化激光器的增益光纤实现了1195 W的1080 nm激光输出,斜率效率达82%。     

105-kW peak-power double-clad fiber laser

A diode-pumped Yb-doped double-clad fiber laser operating in a Q-switched regime is described. By exploiting pulsed pump light and stimulated Brillouin scattering of the gain fiber, a peak power of 105 kW has been demonstrated, which is an order of magnitude greater than that of conventional Q-switched fiber devices. Pulse energy of 0.5 mJ and pulse duration of 5 ns have been achieved.     

High-power side-pumped passively mode-locked Er-Yb fiber laser

A side-pumped double-clad Er-Yb fiber laser passively mode-locked with a saturable absorber is demonstrated for the first time. Pumped with a power of 1 W from a broad-stripe diode laser, an environmentally stable cavity design produces positively chirped 3-ps pulses at a repetition rate of 30 MHz with an average output power of 50 mW. The pulses can be linearly compressed to 330 fs in a length of negative dispersion fiber, whereas nonlinear compression in standard telecom fibers yields 130-fs pulses with pulse energies of 1.2 nJ     

All-glass high NA Yb-doped double-clad laser fibres made by outside-vapour deposition

The first all-OVD, all-glass, high-NA (/spl ges/0.3), double-clad, Yb-doped laser fibres are reported. Yb is incorporated via vapour-phase transport. These fibres yield low passive loss (<3/10 dB/km in core/innerclad at 1310 nm) and high-conversion efficiency, suitable for power scaling and higher reliability. Fibre lasers with output power of 110 W, M/sup 2//spl sime/1.07 and slope efficiency near 80% have been demonstrated.     

980 nm双包层光子晶体光纤激光器

采用内包层直径为200 μm、纤芯直径40 μm,长度45 cm的掺镱双包层光子晶体光纤作为增益介质,915 nm激光二极管（LD）泵浦源,实现了运转于准三能级系统的980 nm连续激光输出。双端输出时,总输出功率为 463.3 mW,斜效率为17.8%;单端输出时,输出功率为543 mW,斜效率为11.6%。     

基于SESAM的全光纤被动锁模光纤激光器

研究实现了一种主振荡功率放大（MOPA）结构的高功率全光纤皮秒级被动锁模掺镱（Yb3+）光纤激光器。种子源为基于半导体可饱和吸收镜（SESAM）的锁模光纤激光器,其为线性腔结构,输出功率为5.97 mW;预放大级采用单模掺镱光纤进行放大,之后经过4倍重复频率倍增系统和两级双包层掺镱光纤放大器,最终实现了平均功率74.3 W,中心波长1063.4 nm,脉冲宽度7.0 ps,重复频率68 MHz的锁模脉冲激光输出。实验中通过对种子光的处理和光纤长度的控制,未出现受激布里渊散射（SBS）、受激拉曼散射（SRS）等非线性效应。     

掺镱双包层光纤激光器研究

主要从速率方程的角度对稳态条件下线型腔内泵浦光和信号光的传播方程进行推导，并在此基础上进行了仿真实验，得到了激光输出功率与输入功率和光纤光度的关系，以及不同泵浦方式对输出功率的影响，最后针对环形腔双包层激光器进行了粗略推导和仿真。     

半导体激光器侧面泵浦双包层光纤技术

泵浦耦合技术是研究高功率光纤激光器和光纤放大器的关键技术,而侧面泵浦耦合技术又是通过泵浦耦合技术获取高功率光纤激光器的未来发展趋势。它是通过双包层光纤的侧面将泵浦光耦合进内包层,对纤芯进行泵浦。目前已经提出并且实现了多种侧面泵浦耦合技术。详细叙述了各种耦合方案的工作原理,并对其耦合效率,输出功率,工艺难易进行了分析和对比,最后根据制作工艺和耦合原理将其进行了分类。     

端面泵浦掺镱双包层光纤激光器功率输出特性研究

基于端面泵浦掺镱双包层光纤激光器的速率方程,应用MATLAB语言编程,分别数值模拟了功率为60瓦前端泵浦、后端泵浦和双端都为30瓦泵浦时掺镱双包层光纤激光器对应的功率输出特性和粒子数密度值特性,增大不同端面输入功率观察输出功率特性,研究得到后端泵浦上能级粒子数分布平坦,输出功率较大,为50.4705瓦。并且增大输入功率时得到双端泵浦输出功率较大。研究结论为提高掺镱双包层光纤激光器功率输出提供理论和实验参考。     

基于马赫-曾德尔干涉仪的可调谐掺镱光纤激光器

A ring-shaped all fiber tunable Yb-doped fiber laser with tuning range over 20 nm is demonstrated by using a fiber Mach-Zenhder interferometer as an intra-cavity filter which is constructed with two 3-dB optical couplers. The method for fabricating the fiber Mach-Zenhder interferometer is detailed. The fiber laser has a moderate milli-Watt level output power over the whole tuning range from 1050 to 1071 nm, a side-band suppression ratio greater than 45 dB, and a bandwidth less than 0.1 nm.