一种基于间接Volterra学习算法的前置补偿器

非线性补偿技术对于的非线性通过补偿信道的非线性特性来提高通信信道的性能越来越重要,非线性补偿器可分为2大类:均衡器和前置补偿器。前者位于非线性信道的输出端而后者则位于非线性信道的输入端。在前置补偿器的基础上,提出一种新的基于Volterra级数前置补偿器,它利用间接学习算法来解决一类前置补偿问题——即信道的特性预先是未知的。这一点P阶逆算法是无法做到的,然后又以正交幅度调制信号(16QAM)验证这种新算法的性能优于P阶逆算法。     

准线性光传输系统色散管理方案的研究

推导了准线性光传输系统中受信道内四波混频、信道内交叉相位调制等信道内非线性效应影响的非线性传输方程,搭建了可构成多种色散管理方案的仿真传输链路,对10Gb/s、40Gb/s、100Gb/s、160Gb/s等四种不同速率的准线性光传输系统的色散管理方案进行了数值分析,分析了幅度抖动与定时抖动的关系,幅度抖动与系统Q值的关系,以及脉冲初始功率与系统Q值的关系。首次得到了单信道准线性光传输系统的最优色散管理方案与系统传输速率相关,并且随着系统传输速率的增加,前色散补偿部分的比例应逐步减少、后色散补偿部分的比例应逐渐增加并可量化的结论。     

一种40 Gbit/s光纤通信系统中的动态色度色散补偿技术

提出了一种用于40 Gbit/s单信道光纤通信系统的动态色度色散(CD)补偿方法.该方法通过检测线路中的色散值,以此作为反馈信号控制动态可调节色散补偿器(TCDC)实现系统的动态CD补偿.TCDC主要由2×2光开关、色散补偿光纤(DCF)和掺铒光纤放大器(EDFA)组成.设计中,增加光开关的数量可以提高色散补偿器件的补偿范围和精度;通过探测传输光信号某一频率(12 GHz)周围窄带范围内的电功率值可实现线路中CD的即时检测.系统的理论补偿量最大可达124 ps/nm.     

利用CFBG补偿色散实现2 015 km 8×10 Gb/s光传输

利用啁啾光纤光栅(CFBG)串联的多波长色散补偿器对长距离传输的8个信道信号进行色散补偿,各个信道波长符合ITU-T标准,波长间隔为100 G.系统采用掺Er3+光纤放大器(EDFA)作为功率放大器,在2 015 km的G.652光纤上无前向纠错(FEC)无电中继实现8×10 Gb/s零误码传输.结果表明,利用CFBG构成的色散补偿器各信道补偿一致性好,CFBG不但能通过滤除带外噪声有效减小长距离传输中由放大器产生的自发辐射噪声(ASE)的积累,提高传输信号的信噪比(OSNR),而且其较低的非线性特性有利于抑止信号劣化,从而有效提高长距离波分复用(WDM)的传输性能,扩展无电中继传输距离.     

一种重构多信道布拉格光栅的混杂算法

由于光纤光敏性的限制,当信道数N变得很大时,采用幅度取样方式制作多信道光栅将变得非常困难.通过相位取样来制作多信道光栅被证明是一种能有效降低峰值折变量的方法.提出一种采用逆散射技术和优化策略的混杂算法有效地设计多信道光栅.由遗传算法进行优化,得到每一个信道相应的相位因子的最优值,改进了多信道光栅复杂的反射谱.再由Layer-peeling算法为依据引入了相位因子后的频谱响应重构光栅.通过对信道间相对相位的优化,制作这种多信道光栅所需的峰值折变量降低为单信道光栅的√N倍.经过数值仿真,得到8信道光栅的峰值折变量大约为单信道光栅的√8倍.     

弱非周期性相位取样啁啾光栅的优化方法

取样光栅可以同时对多个信道进行滤波或色散补偿，所以在波分复用(WDM)系统中有广泛的应用，其中周期相位取样光栅是一种很有前途的设计方法，但周期取样的方法会使取样光栅的所有信道具有相同的色散补偿能力。提出设计弱非周期性相位取样啁啾光栅的优化方法，通过引入一组与信道色散补偿量有关的啁啾控制参数，可使不同信道的色散补偿量存在差异。运用该方法设计出弱非周期的取样光栅后，可用传输矩阵法来模拟该光栅的复反射谱，结果显示通过调整啁啾控制参数，可方便地控制不同信道的色散补偿能力，从而能实现对光纤链路色散与色散斜率的同时补偿，而且取样函数的幅度值的起伏则被完全消除。     

40Gb/s单信道光纤传输系统性能仿真分析

利用Optisystem仿真软件,对40Gb/s单信道传输系统中归零(RZ)调制和非归零(NRZ)调制两种格式进行仿真,并且对基于RZ调制格式下的单信道40Gb/s的色散补偿进行了仿真,比较了前置补偿、后置补偿和对称补偿的传输性能.仿真结果表明:在长距离传输时RZ调制格式优于NRZ调制格式,三种补偿方式中对称补偿效果最优.     

光纤光栅在DWDM系统色散补偿中的应用

色散补偿技术是高速率光通信系统中的重要限制因素，本文分析了两种基于光纤光栅在DWDM系统中用于色散补偿的应用技术，一种为离散信道的色散补偿技术，一种为非离散信道的色散补偿。并简要介绍了对前者用于色散补偿的两种改进方案。     

高双折射取样啁啾光纤光栅的研究与应用

为实现高速光纤通信系统中的偏振模色散(PMD)补偿,提出了基于高双折射线性啁啾光纤光栅(Hi-BiLCFBG)的线性应变梯度悬臂梁作为PMD补偿器,同时考虑到波分复用(WDM)系统中不同信道PMD值不同,提出了取样啁啾(CSP)与周期啁啾(CGP)的等效,利用带有CSP的高双折射取样光纤光栅(Hi-Bi SFBG)制成多信道PMD补偿器,不同信道等效的啁啾系数不同,从而可同时实现多个信道的PMD补偿。实验中,实现了40Gb/s的传输系统中最大58.6 ps的差分群时延(DGD)补偿,补偿后,信号眼图张开度有明显改善,从而证明了该PMD补偿器的有效性与可行性。     

光纤通信系统新码型用于多信道PMD补偿的研究

根据多信道偏振模色散(PMD)的最坏信道补偿方案,以粒子群优化(PSO)算法作为多信道PMD补偿算法,将一些典型的新型调制格式用于多信道PMD补偿,并以两信道PMD补偿系统为例进行了数值模拟,在补偿最坏信道的同时,保障了其他信道的性能,取得了很好的补偿效果.     

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.