158 resultados para Cholinergic Fibers


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报道了一种MOPA式国产单频光纤放大器。该放大器采用连续波单频激光器作为主振荡器,采用我国自行设计和制造的大模场面积掺Yb双包层光纤作为功率放大器,在波长1064 nm处实现了最高7.3 W的连续激光输出,斜率效率为39%,光-光转换效率为26%。此外,对光谱特性及放大的自发发射的抑制也进行了探讨。

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实验报道采用我国自行设计的大模场掺镱双包层光纤,利用简单声光调Q装置,成功实现调Q运转;在1-50kHz调制频率下获得了百纳秒的调Q脉冲,其输出光束质量因子大约为2。当重复频率为1kHz时,获得了脉冲宽度为132ns,能量0.93mJ。同时实验中观察到的调Q脉冲常出现一点锁模现象,针对这一现象进行了讨论。

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缠绕技术通常被用于大模场面积多模光纤激光器的横模控制。将光纤弯曲成不同半径的圆环,多模光纤激光器的高阶横模逐个被抑制并在缠绕半径为20mm时,获得15.4W的单模激光输出。实验研究表明,缠绕半径减小时,由于激光器高阶模式被抑制,其光束质量变好,同时其斜率效率降低。实验测量了多模光纤激光器在不同缠绕半径下的输出性能,并理论计算了各阶模式在不同缠绕半径下的损耗特性。实验测量结果与理论计算结果符合得较好。

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abstract {A large-mode-area (LMA) multimode fiber before and after coiling was studied contrastively in the experiment. Single-transverse-mode output was achieved when the fiber laser was coiled around a mandrel of 65 mm radius. After coiling, beam quality factor of the laser dropped from 1.24 to 1.06 and slope efficiency dropped from 64.7% to 54.3%. When the launched pump power was 149 W, the corresponding output power was 94.7 W and 79.4 W, respectively. However, the brightness of the coiled fiber laser was 1.15 times that of the uncoiled. Coiled modal losses of different modes were also calculated for the fiber employed in the experiment. The measured results agree well with the calculated ones.}

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采用光纤缠绕的方法,来抑制大模场面积(LMA)双包层光纤激光器中的高阶模振荡。将光纤缠绕至两种不同半径,实验测量了相应条件下激光器的输出功率和光束质量因子M2。缠绕半径为165mm时,输出功率为217W,M2为2.96;缠绕半径为52mm时,输出功率为160W,M2为1.38。光纤激光器相应的斜率效率分别为60%和48%。光纤缠绕半径较小时,虽然激光器输出功率减小,但其亮度是大缠绕半径时对应值的3.4倍。

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以短的高掺杂浓度的掺铥硅基光纤为增益介质,采用790 nm波长的激光二极管(LD)为抽运源,得到了波长为2 μm的高功率激光输出。当光纤长度为7 cm时,激光器的阈值泵浦功率为135 mW,最大输出功率为1.09 W,斜率效率为9.6%(相对于耦合进光纤的抽运功率)。该激光器的输出稳定性在5%以内。此外,我们还观察分析了工作温度和其他腔结构参量对该激光器工作性能的影响。

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利用光纤-波导耦合器技术侧面泵浦一根4厘米长的短光纤,我们研制得到了一个红外波长的光纤激光器。该激光器的增益介质是横截面为矩形的掺钕磷酸盐玻璃光纤,其纤芯横截面尺寸为1.5×0.5 毫米,数值孔径为0.2。单横模激光可以通过该矩形光纤的增益-导引效应来获得。最大的激光输出功率为1.05瓦,斜率效率为10%。

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A series-parallel model is introduced to calculate the effective thermal conductivities of hollow claddings of photonic crystal fibers ( PCFs ). The temperature distribution and thermal-optical properties of PCF lasers are studied by solving the heat transfer equations. The average power scaling of the PCF lasers in respect of the thermal effects is also discussed. (c) 2006 Society of Photo-Optical Instrumentation Engineers.

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A series-parallel model is introduced to calculate the effective thermal conductivities of hollow claddings of photonic crystal fibers ( PCFs ). The temperature distribution and thermal-optical properties of PCF lasers are studied by solving the heat transfer equations. The average power scaling of the PCF lasers in respect of the thermal effects is also discussed. (c) 2006 Society of Photo-Optical Instrumentation Engineers.

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Graded-index (GRIN) fiber lens arrays are fabricated from commercial GRIN fibers to collimate a high-power laser diode array. The beam divergence angles are reduced to 4.2 and 14.7 mrad in the fast and slow axes, respectively. The influences of smile and fluctuation in fiber length are discussed. Using an aspherical focal lens system, about 74% power can be launched into a fiber with a numerical aperture (NA) of 0.22 and a core diameter of 400 mu m. (c) 2008 Society of Photo-Optical Instrumentation Engineers.

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abstract {Rare earth ions doped multi-component glass fibers have important application in broad band fiber amplifier and up-conversion fiber lasers. In this paper, the mechanism and the progress of study on rare earth ions doped multi-component glass fibers in broad band fiber amplifier and up-conversion fiber lasers are introduced and reviewed. The questions and the applications of rare earth ions doped multi-component glass fibers in the future are also prospected. Based on the present research progress, it is suggested to further study the tellurite and bismuth glasses, which are used as fiber materials in broad band fiber amplifier. To up-conversion fiber laser, it is still need to further investigate novel glasses, which has low phonon energy and good physical and chemical properties.}

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综述了光子晶体光纤(PCF)不同于传统光纤的各种性质,并详细讨论了光子晶体光纤在通信和光纤激光等领域的新发展。

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Tellurite glass is proposed as a host for broadband erbium-doped fiber amplifiers because of their excellent optical and chemical properties. A new single mode Er3+/Yb3+ codoped tellurite fiber with D-shape cladding geometry is fabricated in this work. When pumped at 980 nm, a broad erbium amplified spontaneous emission (ASE) nearly 100 nm in the wavelength range of 1450-1650 ran around 1.53 mu m is observed. It was found that the emission spectrum from erbium in tellurite glass fibers is almost twice as broad as the corresponding spectrum in tellurite bulk glass. The changes in ASE with regard to fiber lengths and pumping power were measured and discussed. The output of about 2.3 mW from Er3+/Yb3+ codoped tellurite fiber ASE source is obtained under the pump power of 700 mW. The broad 1.53 mu m emission of Er3+ in Er3+/Yb3+ codoped tellurite glass fiber can be used as host material for potential broadband optical amplifier and tunable fiber lasers. (c) 2005 Elsevier B.V. All rights reserved.

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High-uniform nanowires with diameters down to 50 nm are directly taper-drawn from bulk glasses. Typical loss of these wires goes down to 0.1 dB/mm for single-mode operation. Favorable photonic properties such as high index for tight optical confinement in tellurite glass nanowires and photoluminescence for active devices in doped fluoride and phosphate glass nanowires are observed. Supporting high-index tellurite nanowires with solid substrates (such as silica glass and MgF2 crystal) and assembling low-loss microcoupler with these wires are also demonstrated. Photonic nanowires demonstrated in this work may open up vast opportunities for making versatile building blocks for future micro- and nanoscale photonic circuits and components. (c) 2006 Optical Society of America.

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The authors demonstrate a 1.5 mu m wavelength microfiber laser formed by tightening a doped microfiber into a knot in air. The 2-mm-diameter knot, assembled using a 3.8-mu m-diameter microfiber that is directly drawn from Er:Yb-doped phosphate glass, serves as both active medium and resonating cavity for lasing. Single-longitudinal-mode laser with threshold of about 5 mW and output power higher than 8 mu W is obtained. Their initial results suggest a simple approach to highly compact lasers based on doped microscale optical fibers. (c) 2006 American Institute of Physics.