多泵浦拉曼放大器增益特性的仿真与分析

合理简化了多泵浦光纤拉曼放大器功率传输方程,利用多步平均功率法进行数值计算得到了密集波分复用系统信号的合成拉曼增益。借助该简化模型研究了多泵浦光源的个数、输入功率和波长分布对信号拉曼增益的影响,简单分析了实现超宽带平坦拉曼增益的多泵浦波配置原则,为多泵浦光纤拉曼放大器在密集波分复用系统中的应用提供了有价值的参考。     

宽带拉曼光纤放大中的多泵浦源选择方法

理论分析了拉曼光纤放大谱与多波长泵浦光功率和波长的关系.考虑到泵浦光与泵浦光,泵浦光与信号光的拉曼相互作用,得出一个增益数组,增益数组就是离散的宽带拉曼光纤放大增益谱.对任何形态的宽带拉曼光纤放大增益谱,可以设定对应的增益数组,把泵浦光功率和波长组成二维坐标系,遍取坐标系中的各点,求出各组点对应的增益数组,找出最接近设定的增益数组,这组泵浦光功率及波长就是最优的解决方案.     

多泵浦光纤拉曼放大器增益性能研究

FRA(光纤拉曼放大器)增益的峰值位置由泵浦波长决定,不同波长的泵浦光在不同的信号波长处产生最大增益。为获得最佳的FRA增益特性,采用多波长泵浦FRA理论模型,利用Optisystem软件建立了多泵浦FRA系统,通过系统仿真,研究了光纤通信系统中FRA的增益特性,分析了传输距离、纤芯有效面积、泵浦光功率和泵浦数量等因素对FRA增益的影响,确定了影响FRA增益的最佳参数,验证了FRA仿真系统的正确性和设计方案的可行性。     

反向拉曼光纤放大器(FRA)的瞬态效应分析

本文首先提出子泵浦概念、建立分析拉曼光纤放大器瞬态效应的数学模型 ,然后给出单泵浦单信道拉曼放大器发生瞬态效应时信号功率、信号增益和泵浦功率的变化曲线 ;在分析多泵浦多信道拉曼放大器瞬态效应时得到了上下短波长信道对剩余信道稳态增益影响最小 ,上下长波长信道对剩余信道稳态增益影响最大的结论。     

反向拉曼光纤放大器（FRA）的瞬态效应分析

本文首先提出于泵浦概念、建立分析拉曼光纤放大器瞬态效应的数学模型，然后给出单泵浦单信道拉曼放大器发生瞬态效应时信号功率、信号增益和泵浦功率的变化曲线；在分析多泵浦多信道拉曼放大器瞬态效应时得到了上下短波长信道对剩余信道稳态增益影响最小，上下长波长信道对剩余信道稳态增益影响最大的结论。     

多泵浦光纤拉曼放大器增益平坦性研究

针对掺铒光纤放大器的增益竞争特性,在Rsoft公司提供的仿真平台上搭建了长距离分布式多泵浦光纤拉曼放大器实验模型.在分析泵浦光与泵浦光、泵浦光与信号光的拉曼相互作用的基础上,仿真过程中还充分考虑瑞利散射、自发散射以及信号光传输过程中非线性的影响,分别对它的前向与后向泵浦功率分配、泵浦间隔分布、等间隔泵浦功率分配进行了优化,并在国家建议标准中的8信道带宽内得到了增益波动最小的配置规律.     

基于粒子群优化算法的双向多泵浦光纤拉曼放大器增益研究

基于石英光纤作为增益介质,采用龙格-库塔法、打靶法求解多波长双向泵浦光纤拉曼放大器的功率耦合波方程,得到拉曼放大器的增益带宽,平均增益,增益平坦度以及泵浦光和信号光沿光纤的分布。再通过粒子群优化算法对同一数量泵浦光不同排列双向系统进行逐个优化分析,在14种双向泵浦结构中选出性能较优的三种结构,再对它们优化参数设置,最终得到性能最优的双向泵浦结构BBFF。研究结果表明:在仅有四个泵浦光的情况下,双向多泵浦结构BBFF具有最优的平均增益和增益平坦度,并且得到了开关增益为23.1665 dB,增益平坦度为0.794 dB的双向泵浦结构。     

基于粒子群算法的拉曼光纤放大器的多抽运源优化

基于粒子群算法(PSO)提出了一种优化多波长抽运拉曼光纤放大器的新方法。只要给定信号光的波长分布、功率、抽运光的个数、抽运光的波长和功率变化范围．再根据其他已知的光纤参数．就能优化出满足指定平均开关增益大小、指定增益平坦度所需的抽运源参数．包括各个抽运源的波长和功率。采用该方法对一个C波段的拉曼光纤放大器进行了优化．仅应用两个抽运光源就实现了平均开关增益分别为32dB、20dB、l7dh相应最大增益波动分别为的拉曼光纤放大器的设计．得到了各抽运光源的优化波长和优化功率。     

宽带光纤拉曼放大器的优化设计􀀂

研究优化设计宽带光纤拉曼放大器平坦增益带宽的方法。通过研究多波长后向泵浦光纤拉曼放大器的传输方程，分别用模拟煺火算法及四阶阿当方法迭代出各泵浦波频率及输入功率的大小。可设计出满足增益平坦度要求的宽带光纤拉曼放大器。设计了两个光纤拉曼放大器，一个采用双波长泵浦，得到的平坦增益带宽为50nm，增益不平坦度小于1dB。另一个采用四波长泵浦，得到的平坦增益带宽为80nm，增益不平坦度小于1dB。所得结果证明提出的优化设计方法对于设计多波长泵浦平坦增益带宽光纤拉曼放大器是一种有效的方法。     

反向多波长泵浦宽带FRA泵浦配置的一种优化方法

提出了一种基于粒子群算法(PSO)优化设计反向多波长泵浦光纤拉曼放大器(FRA)的方法.具体实施中应用PSO对6波长反向泵浦FRA的泵浦波长和泵浦功率共12个变量同时进行优化,然后依据泵浦光功率演变规律改进PSO算法,较好地克服了PSO优化精度低的缺点,最后得到了增益带宽100 nm,增益波动小于0.6 dB的优化结果,这为优化设计超宽带光纤拉曼放大器提供了一种可行的方法.     

Resolution Enhancement Technology:Integrated Process Solutions using OPC

DUV lithography, using the 248 nm wavelength, is a viable manufacturing option for devices with features at 130 nm and less. Given the low kl value of the lithography, integrated process development is a necessary method for achieving acceptable process latitude. The application of assist features for rule based OPC requires the simultaneous optimization of the mask, illumination optics and the resist.Described in this paper are the details involved in optimizing each of these aspects for line and space imaging.A reference pitch is first chosen to determine how the optics will be set. The ideal sigma setting is determined by a simple geometrically derived expression. The inner and outer machine settings are determined, in turn,with the simulation of a figure of merit. The maximum value of the response surface of this FOM occurs at the optimal sigma settings. Experimental confirmation of this is shown in the paper.Assist features are used to modify the aerial image of the more isolated images on the mask. The effect that the diffraction of the scattering bars (SBs) has on the image intensity distribution is explained. Rules for determining the size and placement of SBs are also given.Resist is optimized for use with off-axis illumination and assist features. A general explanation of the material' s effect is discussed along with the affect on the through-pitch bias. The paper culminates with the showing of the lithographic results from the fully optimized system.     

Cost-effective test solutions for smart card and other integrated flash applications

From its emergence in the late 1980s as a lower cost alternative to early EEPROM technologies, flash memory has evolved to higher densities and speedsand rapidly growing acceptance in mobile applications.In the process, flash memory devices have placed increased test requirements on manufacturers. Today, as flash device test grows in importance in China, manufacturers face growing pressure for reduced cost-oftest, increased throughput and greater return on investment for test equipment. At the same time, the move to integrated flash packages for contactless smart card applications adds a significant further challenge to manufacturers seeking rapid, low-cost test.     

Theoretical analysis of the relationship between the Brillouin gain coefficient and the strain in the optical-fiber sensors

The relation between the power of the Brillouin signal and the strain is one of the bases of the distributed fiber sensors of temperature and strain. The coefficient of the Bfillouin gain can be changed by the temperature and the strain that will affect the power of the Brillouin scattering. The relation between the change of the Brillouin gain coefficient and the strain is thought to be linear by many researchers. However, it is not always linear based on the theoretical analysis and numerical simulation. Therefore, errors will be caused if the relation between the change of the Brillouin gain coefficient and the strain is regarded as to be linear approximately for measuring the temperature and the strain. For this reason, the influence of the parameters on the Brillouin gain coefficient is proposed through theoretical analysis and numerical simulation.     

An improved parallel thinning algorithm with two subiterations

The parallel thinning algorithm with two subiterations is improved in this paper. By analyzing the notions of connected components and passes, a conclusion is drawn that the number of passes and the number of eight-connected components are equal. Then the expression of the number of eight-connected components is obtained which replaces the old one in the algorithm. And a reserving condition is proposed by experiments, which alleviates the excess deletion where a diagonal line and a beeline intersect. The experimental results demonstrate that the thinned curve is almost located in the middle of the original curve connectivelv with single pixel width and the processing speed is high.     

Novel fiber-optical interferometer with miniaturized probe for in-hole measurements

Today, micro-system technology and the development of new MEMS （Micro-Electro-Mechanical Systems） are emerging rapidly. In order for this development to become a success in the long run, measurement systems have to ensure product quality. Most often, MEMS have to be tested by means of functionality or destructive tests. One reason for this is that there are no suitable systems or sensing probes available which can be used for the measurement of quasi inaccessible features like small holes or cavities. We present a measurement system that could be used for these kinds of measurements. The system combines a fiber optical, miniaturized sensing probe with low-coherence interferometry, so that absolute distance measurements with nanometer accuracy are possible.     

Development of the readout system for waveguide multilayer optical card

Waveguide multilayer optical card （WMOC） is a novel storage device of three-dimensional optical information. An advanced readout system fitting for the WMOC is introduced in this paper. The hardware mainly consists of the light source for reading, WMOC, motorized stages addressing unit, microscope imaging unit, CCD detecting unit and PC controlling ＆ processing unit. The movement of the precision motorized stage is controlled by the computer through Visual Basic （VB） language in software. A control panel is also designed to get the layer address and the page address through which the position of the motorized stages can be changed. The WMOC readout system is easy to manage and the readout result is directly displayed on computer monitor.     

Study of waveguide coupling efficiency in hybrid silicon lasers

This paper presents a new method to increase the waveguide coupling efficiency in hybrid silicon lasers. We find that the propagation constant of the InGaAsP emitting layer can be equal to that of the Si resonant layer through improving the design size of the InP waveguide. The coupling power achieves 42% of the total power in the hybrid lasers when the thickness of the bonding layer is 100 nm. Our result is very close to 50% of the total power reported by Intel when the thickness of the thin bonding layer is less than 5 nm. Therefore, our invariable coupling power technique is simpler than Intel＇s.     

Collinear phase-matching study of terahertz-wave generation via difference frequency mixed in GaAs and Inp

The collinearly phase-matching condition of terahertz-wave generation via difference frequency mixed in GaAs and InP is theoretically studied. In collinear phase-matching, the optimum phase-matching wave hands of these two crystals are calculated. The optimum phase-matching wave bands in GaAs and lnP are 0.95-1.38μm and 0.7-0.96μm respectively. The influence of the wavelength choice of the pump wave on the coherent length in THz-wave tuning is also discussed. The influence of the temperature alteration on the phase-matching and the temperature tuning properties in GaAs crystal are calculated and analyzed. It can serve for the following experiments as a theoretical evidence and a reference as well.     

Effects of the alloy compositions on the phonon-polaritons in ternary mixed crystals

Composition dependence of bulk and surface phonon-polaritons in ternary mixed crystals are studied in the framework of the modified random-element-isodisplacement model and the Bom-Huang approximation. The numerical results for Several Ⅱ - Ⅵ and Ⅲ- Ⅴ compound systems are performed, and the polariton frequencies as functions of the compositions for ternary mixed crystals AlxGa1-xAs, GaPxAS1-x, ZnSxSe1-x, GaAsxSb1-x, GaxIn1-xP, and ZnxCd1-xS as examples are given and discussed. The results show that the dependence of the energies of two branches of bulk phonon-polaritons which have phonon-like characteristics, and surface phonon-polaritons on the compositions of ternary mixed crystals are nonlinear and different from those of the corresponding binary systems.     

New insert layer structure OLEDs

An insert layer structure organic electroluminescent device（OLED） based on a new luminescent material （Zn（salen）） is fabricated. The configuration of the device is ITO/CuPc/NPD/Zn（salen）/Liq/LiF/A1/CuPc/NPD/Zn（salen）/Liq/LiF/A1. Effective insert electrode layers comprising LiF（1nm）/Al（5 nm） are used as a single semitransparent mirror, and bilayer cathode LiF（1 nm）/A1（100 nm） is used as a reflecting mirror. The two mirrors form a Fabry-Perot microcavity and two emissive units. The maximum brightness and luminous efficiency reach 674 cd/m^2 and 2.652 cd/A, respectively, which are 2.1 and 3.7 times higher than the conventional device, respectively. The superior brightness and luminous efficiency over conventional single-unit devices are attributed to microcavity effect.