基于光相位信号延时自相干的相位信息高速实时取样系统

提出了一种基于光相位信号自相干的高速光相位实时取样方案。利用时延为10ps的延时干涉仪(DI),将待测光信号的相位信息转换为强度信息;再在高非线性光纤(HNLF)中,利用四波混频(FWM)效应对强度信号进行取样。在接收端,利用不同中心波长的光滤波器(OBPF)即可滤出不同时间点的取样信号,从而在光域同时完成高速光相位信息的实时取样和取样信号的串-并转换。本文方案具有成本低、对测信号码率和波长不敏感的优点。实验中,对9GHz正弦调制以及10Gb/s非归零码调制的光相位信号实现了100G/s的高速实时取样系统,并转换为10路10G/s取样信号输出,最终恢复取样光信号的相位波形。     

光纤传输系统中基于相位预调制的信号整型

利用相位预调制技术解决高速长距离光纤传输系统中面临的接收灵敏度降低和色散容限问题。通过在发射端对非归零(NRZ)的光信号进行比特同步相位预调制,使非归零码在传输过程中得到波形重整,演变为归零(RZ)的波形,从而提高眼图开启度。实验观测了普通非归零码和相位预调制的非归零码在不同相位调制深度和色散下的光谱、眼图和功率代价。10Gb/s的传输结果表明,链路色散绝对值小于1000ps/nm时,施加相位预调制的非归零信号功率代价小于1dB,比普通非归零信号具有更高的接收灵敏度和更低的色散功率代价。因此,基于相位预调制的信号整型技术可减轻系统对光信噪比和色散管理的要求,延长传输距离。     

基于光纤的RZ-DPSK全光再生技术的研究

文章针对基于光纤自相位调制(SPM)效应和四波混频(FWM)效应的全光再生技术,分析了归零差分相移键控(RZ-DPSK)调制信号在SPM效应下再生的局限性,指出只有将相位调制转换为幅度调制才可用此方法实现;同时研究了利用FWM效应实现再生时,在保证转换效率的前提下泵浦光和信号光波长与零色散波长之间需要满足的关系,以得到适合再生的转移函数.     

基于光纤中四波混频效应的多信道波长转换性能的数值分析

高效多信道波长转换技术对于将来灵活的全光网络应用具有重要的意义。在本文中我们从数值上分析了幅度调制信号,相位调制信号,以及混合幅度调制信号和相位调制信号的多信道波长转换技术。本文同时也讨论了受激布里渊散射效应及其对于基于四波混频效应的高效波长转换技术的影响。分析结果表明差分相位调制信号（DPSK）更加适合基于四波混频效应的多信道波长转换技术,因为多信道OOK波长转换的信号将会受到无法避免的码型相关损耗效应的影响。在将来的应用中,当调制格式由传统的OOK格式部分升级为DPSK格式的时候,在多信道波长转换情况下的OOK信号对于升级的DPSK信号的影响必须要仔细考虑,并且这种影响随着OOK信道数目的增加变得更加严重。因此我们可以得出如下结论,DPSK信号更加适合于传输和多信道波长转换的需要,尤其是在长距离传输和高比特速率的系统中。     

BPSK‒QPSK和QPSK‒16QAM的光调制格式转换

信号在调制方式不同的系统之间传输时,需要对信号调制格式进行转换,而调制格式转换通常在电信号上进行,要将光信号恢复成电信号。在电信号上进行调制格式转换后,再经电光调制器变换成光信号发射。频繁的光电或电光转换通常会增加系统成本,针对该问题,提出了利用相干叠加在光域上实现二进制相移键控(BPSK)到正交相移键控(QPSK)以及QPSK到正交幅度调制(16QAM)的调制格式转换的方法。实验通过Optisystem软件对转换模型进行仿真,采用10 Gpbs伪随机信号作为测试信源,通过星座图观测出信号成功转换为QPSK和16QAM;并在不同光信噪比、光源线宽和信号功率下对转换模型与直接QPSK、16QAM传输模型进行误码分析对比,在相同条件下转换模型和直接传输的误码率高度保持一致,表明这种调制格式转换方法具有较高的稳定性和准确性,能够适用于不同系统间的信号传输。     

在微结构光纤中实现四进制向二进制的全光转换

提出并实验了一种基于高非线性色散平坦微结构光纤的四进制光信号向二进制光信号的全光转换方案。由于自相位调制(SPM)效应,不同峰值功率的ps光脉冲经过微结构光纤传输后可获得不同展宽程度的输出频谱。基于以上原理,通过滤波可将1路10Gb/s的四进制信号转化成3路不同波长的10Gb/s二进制信号,再将3路信号进行适当的时延和衰减,最后耦合成为1路20Gb/s的二进制信号,实验获得的转换信号消光比达到3.2dB。     

交叉相位调制对密集波分复用系统性能的影响

研究了交叉相位调制对密集波分复用系统性能的影响 ,分析了干扰信道为正弦调制时交叉相位调制效应对考察信道相位的影响 ,在此基础上 ,建立任意信号通过具有交叉相位调制效应的信道时的系统模型 ,并将该模型应用于基带不归零码数字信号传输的情形 ,计算了由交叉相位调制引起的系统光功率代价。结果表明 ,交叉相位调制效应对高速率调制系统的性能具有一定的影响 ,应该在系统设计时的功率预算中予以考虑。     

BPSK光调制系统中电平转换电路设计

电光相位调制方式已经成为国内国外光传输技术研究的焦点。相比于基于开关键控(OOK)调制方式的传输系统,基于电光相位调制方式的传输系统的接收机灵敏度和非线性容限都较高。所以系统升级首选电光相位调制方式。本文设计了BPSK光调制系统中的电平极性转换电路,并通过软件仿真验证其可行性。     

基于HNLF的RZ到NRZ的全光码型转换

数值仿真分析了利用高非线性光纤(HNLF)的交叉相位调制(XPM)效应实现归零(RZ)码到非归零(NRZ)码的转换,并讨论了RZ信号占空比、光纤色散对转换后NRZ信号Q因子的影响.数值结果表明:转换后NRZ码的Q值受输入RZ信号占空比的影响;而且RZ信号与连续的探测光之间的色散差也严重影响转换后NRZ信号的Q因子值.     

载波重用微波光纤矢量信号传输系统性能研究

提出了一种基于双边带(DSB)部分载波抑制调制(OCS)方式的微波光纤传输(ROF)系统结构,实现了矢量信号的传输以及调制方式由8PSK到QPSK的转换,并使用光纤Bragg光栅(FBG)实现了光载波的重新使用,降低了系统的成本。分析了实验原理并搭建了实验链路,在中心站,采用光OCS方案产生并倍频加载了携带有1 Mbps的8PSK矢量信号的5 GHz微波信号,实验结果表明,在基站,使用FBG实现光载波重用的同时,微波信号频率由5 GHz上转换为10 GHz,传输的矢量信号调制方式由8PSK变为QPSK。通过光谱可以看出,实验链路成功实现了50 GHz nm波矢量信号的产生和传输。     

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.     

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.     

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.     

Teleportation of an arbitrary unknown N-qubit entangled state under the controlling of M controllers

A new quantum protocol to teleport an arbitrary unknown N-qubit entangled state from a sender to a fixed receiver under M controllers(M < N) is proposed. The quantum resources required are M non-maximally entangled Greenberger-Home-Zeilinger (GHZ) state and N-M non-maximally entangled Einstein-Podolsky-Rosen (EPR) pairs. The sender performs N generalized Bell-state measurements on the 2N particles. Controllers take M single-particle measurement along x-axis, and the receiver needs to introduce one auxiliary two-level particle to extract quantum information probabilistically with the fidelity unit if controllers cooperate with it.     

Diode-end-pumped Nd:YVO4/LBO lasers with 4.2W continuous-wave output at 457 nm

A continuous-wave (CW) 457 nm blue laser operating at the power of 4.2 W is demonstrated by using a fiber coupled laser diode module pumped Nd: YVO4 and using LBO as the intra-cavity SHG crystal With the optimization of laser cavity and crystal parameters, the laser operates at a very high efficiency. When the pumping power is about 31 W, the output at 457nm reaches 4.2 W, and the optical to optical conversion efficiency is about 13.5% accordingly. The stability of the out putpower is better than 1.2% for 8 h continuously working.     

Call for Papers

正Wireless Body-area Networks The last decade has witnessed the convergence of three giant worlds:electronics,computer science and telecommunications.The next decade should follow this convergence in most of our activities with the generalization of sensor networks.In particular with the progress in medicine,people live longer and the aging of population will push the development of wireless personal networks     

Call for Papers—Feature Topic,Vol.12,No.7,2015

正Information Centric Networking Information-Centric Networking(ICN) is an emerging direction in Future Internet architecture research,gaining significant tractions among academia and industry.Aiming to replace the conventional host-to-host communication model by a data-centric model,ICN treats data content as the first