ArF准分子激光器的窄线宽可调谐运转及注入放大

在一台快放电泵浦的ＡｒＦ准分子激光振荡放大系统的振荡级上采用光栅、扩束镜、光阑等腔内元件，用组合输出镜获得了线宽小于０．１ｎｍ，调谐范围～１ｎｍ的激光输出。注入到非稳腔结构的放大级，注入后放大级效率提高了约５０％，获得了平均３０ｍＪ／脉冲的高光束质量的窄线宽可调谐激光，最大单脉冲能量＞５０ｍＪ，并进行了氧气的吸收光谱实验。     

注入锁定铜蒸气激光器输出光脉冲方向性的时间演化过程

介绍一种采用小孔光阑穿透来测量激光脉冲方向性的时间演化过程方法，并对放大倍率为Ｍ＝１０（振荡器Ｍ＝３０）的注入锁定铜激光器输出光脉冲方向性时间分辨过程进行了测量。结果表明：在激光脉冲的形成过程中，输出光方向性越来越好，相应发散角由～１．０ｍｒａｄ连续地减小到０．１２ｍｒａｄ。最后对实验结果进行了讨论。     

新颖应用电路·实用电路集

６１５－三相正弦波发生器　　该图说明了如何用一个ＵＡＦ４２型状态可变的滤波器和一些电阻器和二级管制作三相正弦波振荡器。有３个输出节点：高通输出、带通输出以及低通输出。带通和低通输出节点处的信号与高通节点处信号的相位差分别为９０°和１８０°。芯片上的辅助运算放大器可用作缓冲器或放大器级。　　根据　ｆｏｓｃ＝１／２πＲＣ用电阻器ＲＦ１和ＲＦ２设置振荡频率,其中Ｒ＝ＲＦ１＝ＲＦ２且Ｃ＝Ｃ１＝Ｃ２＝１０００ｐＦ用ＵＡＦ４２状态可变滤波器得到的最高振荡频率为１００ｋＨｚ。但当振荡频率高于１０ｋＨｚ,会出现…     

自锁模掺钛蓝宝石激光超短脉冲脉宽小于31 fs

自锁模掺钛蓝宝石激光超短脉冲脉宽小于３１ｆｓ我们利用自己生长出的高质量、高掺杂的掺钛蓝宝石晶体，获得了高效率的超短脉冲激光输出。Ｔｉ３＋：Ａｌ２Ｏ３激光棒尺寸为４×４×５ｍｍ３，吸收系数α４９０＝６．２ｃｍ－１，品质因数ＦＯＭ＝１２０。采用自锁模技术...     

激光波长可交替变换的染料激光器

本文主要介绍一种激光输出波长可交替变换的染料激光器．该染料激光器的泵浦源是脉冲Nd：YAG激光器的3次谐波．输出波长为0．355μm，脉冲宽度为10ns；重复频率为10Hz，激光能量为5～30mJ．该染料激光器的光学结构（光路图略）是采用光栅调谐、棱镜扩束、振荡级染料池、输出腔镜及放大级染料池等组成．0．355μm的Nd：YAG激光通过柱镜镜组泵浦在两级染料池上，经振荡、放大，产生所要求的染料激光．为获得染料激光输出的不同波长的交替变换，则是在上述染料激光器光路系统中播人一个波长选择器组件，这种波长选择器就是一个旋转的棱镜组…     

LD抽运高重复频率四通放大MOPA系统中的光纤相位共轭研究

报道了利用多模光纤作为相位共轭镜应用于重复频率100Hz。脉宽20ns的电光调Q四通放大LD抽运激光器的实验研究。由于光纤受激布里渊散射(SBS)存在的阈值效应，可以抑止使用平面全反镜的四通放大系统中难以克服的放大级自振荡(SO)和放大自发辐射(ASE)效应．以获得高能量高光束质量的激光输出。实验中在20ns．100Hz和注入光纤能量4．6mJ的情况下获得了4．1mJ的1064nm的基模激光输出。激光光束模式接近TEMoo模．且脉宽被压缩至4．7ns。在使用了光纤相位共轭镜的四通放大技术后，很好地补偿了由板条放大器热效应造成的光斑畸变。输出光斑很好地复原了振荡级输出光斑的光强空间分布。     

宽带GaAs MMIC放大器

Ｍ／Ａ-ＣＯＭ研制的ＭＡＡＭ２８０００-Ａ１型宽带ＭＭＩＣ放大器的工作频率为２～８ＧＨｚ,它采用２级放大,单电源１０Ｖ供电,具有较好的增益平坦度,输入输出阻抗均为５０Ω,增益为１７ｄＢ,增益平坦度为±０．５ｄＢ,在２～４ＧＨｚ、４～６ＧＨｚ和６～８ＧＨｚ时的最大噪声分别为８．０ｄＢ、６．５ｄＢ和６．０ｄＢ,输入和输出驻波比分别为１．６和１．５,输入ＩＰ３为+７ｄＢｍ,输出１ｄＢ压缩为+１．４ｄＢｍ,反向隔离为３５ｄＢ,最大偏压电流为１００ｍＡ。该器件采用廉价的小型８脚陶瓷封装,不需要任何外部元件,可用于卫星通…     

激光二极管抽运的主振荡级与功率放大器结构Nd∶YVO4激光器

为了实现固体激光器高功率、高光束质量的输出,设计了一种激光二极管(LD)阵列抽运的主振荡级与功率放大器(MOPA)结构的Nd∶YVO4激光器。该激光器的振荡级采用平-平谐振腔结构,并使用棱镜组对激光二极管阵列的抽运光整形,消除了激光二极管阵列抽运光不对称对振荡器输出光束质量的影响,在连续工作条件下获得了6.1 W的激光输出,其光束质量M2因子为M2x=1.14,M2y=1.13,光-光转换效率为25.6%。放大级采用具有近共焦、非稳腔特点的折叠光路结构,使振荡级激光光束10次通过放大级晶体,并且有效地抑制了放大自发辐射(ASE)和寄生振荡。在振荡级以6.1 W注入放大器时,得到最大输出功率26.8 W,此时放大器提取效率为29.1%,输出光束质量M2因子为M2x=2.08,M2y=1.92。     

脉冲锁模Nd:YAG激光器的实验研究

本文主要介绍在脉冲锁模ＹＡＧ激光实验中,采用了一种新型自滤波非稳腔（ＳＦＵＲ）和直线对撞被动锁模方式,使激光器具有结构简单、光束质量好、输出激光稳定可靠等优点． １９８４年意大利Ｐ．Ｃ．Ｇｏｂｂｉ等人首先提出用负分支自滤波非稳腔（ＳＦＵＲ）改进高增益激光系统,随后又实现了有效的锁模运用．这种腔型含有场限制光阑,光阑小孔半径 ａ＝ ０．６１ｆ２λ,位于焦距分别为ｆ１．ｆ２的两个凹面全反镜Ｍ１和Ｍ２的公共焦点上．当平面波从Ｍ２反射回来只有Ａｉｒｙ斑部分允许通过ＹＡＧ增益介质,即谐振腔内产生均匀的 Ａｉｒ…     

单脉冲皮秒Nd:YAG倍频激光器

介绍一种氙灯抽运的单脉冲皮秒Nd:YAG倍频激光器,该激光器由振荡级、单脉冲选取、放大级、倍频和扩束准直等部分组成,激光器的振荡级利用被动锁模染料产生的锁模序列脉冲激光,经过单脉冲选择部分选取出其中的一个单脉冲,此单脉冲经过激光器放大部分的放大和倍频晶体的倍频后,激光器最终可输出能量达到120 mJ、波长为532 nm的单脉冲激光.该激光器的振荡级采用自行研制的光漂移控制仪,使激光器输出激光的外触发同步精度优于2μs.     

双曲余弦-高斯光束的相干模分解

利用傅里叶变换和正交模系展开法,推导出了双曲余弦—晶斯光束的M2因子和归一化模系数的解析表达式,从而建立了双曲余弦-高斯光束的相干模分解理论。提出了一种在实验室中产生双曲余弦-高斯光束的简单方法。     

LD端面抽运Nd:YLF/Nd:YAG多波长脉冲激光器

报道了一台激光二极管(LD)双端面抽运Nd:YLF和Nd:YAG双晶体串接多波长输出脉冲激光器。在抽运能量40.5mJ,电光调Q重复频率500Hz的工作条件下,获得单脉冲能量约为6mJ的1064nm/1053nm双波长激光脉冲输出,光-光转换效率约为14.8%。相同抽运条件下在腔内插入I类相位匹配LBO晶体作为非线性频率转换器,获得了脉冲总能量为3.6mJ的526.5、529.0、532.0nm三波长同时输出,由抽运光到输出绿光脉冲的转换效率约为8.9%,测得光束质量因子分别为M2x=1.61,My2=1.25。     

Tm:YAP激光晶体光谱参数的计算

采用丘克劳斯基(Czochralski)法生长了Tm:YAP晶体,研究了该晶体在室温下的吸收光谱和荧光光谱.结果表明,Tm:YAP晶体在689.5 nm和795 nm左右有较强的吸收峰,分别对应于3H6→3F3和3H6→3H4的能级跃迁,半峰全宽(FWHM)分别为22.5 nm和30 nm,吸收截面分别为1.89×10-20 cm2和1.35×10-20 cm2.荧光光谱表明Tm:YAP晶体发射波长为1.89μm,相应的荧光寿命为13.90 ms,发射截面为1.58×10-19 cm2.根据乍得-奥菲特(Judd-Ofelt)理论计算了Tm3+在Tm:YAP晶体中的强度参数:Ω2=1.4560×10-20cm2,Ω4=2.0673×10-20 cm2,Ω6=0.3181×10-20 cm2.结果表明,Tm:YAP晶体具有宽的吸收峰、长荧光寿命和较大的积分发射截面的性质,非常适合于激光二极管(LD)抽运,有利于获得低阈值高效率的2μm波段激光输出.     

Rearrangeable f-cast multi-log2 N networks

Multi-log2 N networks (or vertically stacked banyan networks) have been an attractive class of switching networks due to their small depth O(logN), absolute signal loss uniformity and good fault tolerance property. Recently, F.K.Hwang extended the study of multi-log2 N networks to the generalf-cast case, which covers the unicast case (f = 1) and multicast case (f = N) as special cases, and determined the conditions for these networks to be f-cast strictly nonblocking when the fan-out capability is available at both the input stage and middle banyan stage. In this paper, we study the rearrangeable f-cast multilog2 N networks under both node-blocking scenario (relevant to photonic switches) and link-blocking scenario (relevant to electronic switches). In particular, we consider the following three fan-out cases in our study: 1) no restriction on fan-out capability; 2) input stage has no fan-out capability; 3) middle banyan stage has no fan-out capability. We determine the necessary conditions for the first two cases while obtaining the necessary and also sufficient condition for the third one.     

Signal integrity and design consideration of an MCM for videographic acceleration

This paper introduces a cost effective multichip module (MCM) for video graphic acceleration (VGA) of portable computers. A 1.7 million gate graphic processor IC and two 8 M byte DRAM chips have been integrated into a 31×31 mm² 4-layer PBGA. Signal integrity measurement and analysis has been performed to optimize performance of the present design and a direction for improvement for the next generation product. This study confirms that more consideration given to the MCM application at the IC design stage will maximize MCM performance     

Hf:Fe:LN晶体生长与光折变性能的研究

原料采用在Fe(0.03%,质量分数):LN中掺进摩尔分数为(1%、2%、4%、5%)的HfO2,再次采用提拉法生长Hf:Fe:LN晶体.抗光损伤阈值测试表明,Hf(5%,摩尔分数):Fe:LN晶体抗光损伤能力比Hf(1%,摩尔分数):Fe:LN晶体提高2个数量级以上.以二波耦合光路测试晶体的衍射效率,写入时间和擦除时间,并计算出光折变灵敏度和动态范围.结果表明,Hf:Fe:LN晶体全息存储性能优于Fe:LN晶体.     

GSM光束经过角棱锥之后光束质量的改变

本文从Wigner分布函数出发，计算GSM（GaussianSchell－Model）光束经过角棱锥之后光束质量因子（M2因子）的变化。结果表明，经过角棱锥之后，光束质量因子的增量依赖于输入的光束半径、角棱锥材料的折射率和角棱锥角度。     

Pareto ANOVA analysis for CMOS 0.18 µm two-stage Op-amp

This paper presents a Pareto ANOVA analysis technique as an alternative way to analyze some selected optimization parameters in two-stage op-amp. Three input parameters and two output parameters based on standard L₂₇(3¹³) in Taguchi method have been chosen in this optimization methodology. The input parameters are selected based on the value of W/L ratio at three transistors which are transistor M8, M9 and M7. Two types of outputs have been aimed to optimize which are power dissipation and gain. This op-amp has been constructed by using CMOS technology 0.18 µm and the results have been verified by using a Mentor Graphic EldoSpice. From the analysis, it is found that level 16 has been chosen as an optimal combination produced by a Taguchi method. After this, Pareto ANOVA technique will be applied to analyze the effect of selected input parameters in achieving optimum gain and power of the two stage op-amp. The analysis showed that the value of W/L ratio at transistor M9 gives a major impact on power dissipation and value of W/L ratio at transistors M8 and M9 give a major impact on gain. This study also shows that Pareto ANOVA is an easier method to analyze circuit parameters.     

RSFQ circuitry realized in a SINIS technology process

We have developed integrated circuits in rapid single flux quantum (RSFQ) impulse logic based on intrinsically shunted tunnel junctions as the active circuit elements. The circuits have been fabricated using superconductor-insulator-normalconductor-insulator-superconductor (SINIS) multilayer technology. The paper presents experimental results of the operation of various RSFQ circuits realized in different designs and layouts. The circuits comprise dc/SFQ and SFQ/dc converters, Josephson transmission lines (JTLs), T-flipflops, and analog key components. Functionality has been proved; the circuits have been found to operate correctly in switching. The circuits investigated have a critical current density of j_C=400 A/cm² and a characteristic voltage of V_C=165 μV, the area of the smallest junction is A=24 μm². The junctions exhibit nearly hysteresis-free current-voltage characteristics (hysteresis: less than 7%), the intra-wafer parameter spread for j_C is below ±8%. The margins of the bias current I_b of the circuits have been experimentally determined and found to be larger than ±24%. At preset, constant values of I_b, the range of a separate bias current I_bsw fed to a switching stage integrated between two segments of JTL's is fully covered by the operation margins which are larger than ±56%     

Preparation and thermoelectric properties of PEDOT:PSS coated Te nanorod/PEDOT:PSS composite films

PEDOT:PSS coated Te (PCTe) nanorod/PEDOT:PSS composite films were prepared by a drop-casting technique. H₂SO₄ treatment was employed to enhance thermoelectric (TE) properties of the composite films. The addition of PCTe nanorods increased both the electrical conductivity and the Seebeck coefficient of the composite films. An optimized power factor of 141.9 μW/mK² was obtained for the film containing 90 wt% PCTe nanorods treated with 12 M H₂SO₄ at room temperature, which was 2.75 times as high as that of the untreated composite film, corresponding to the electrical conductivity and Seebeck coefficient of 204.6 S/cm and 83.27 μV/K, respectively. XPS and GIWAXS analysis revealed the removal of insulating PSS units and the rearrangement of PEDOT chains after the H₂SO₄ treatment. Finally, a 9-leg TE generator prototype was fabricated using the optimized composite film. The maximum output power and area output power density produced from the prototype were 47.7 nW and 57.2 μW/cm², respectively, at the temperature difference of 40 K.