微结构硫化物光纤中中红外超连续谱的产生

采用微结构硫化物光纤,以非线性薛定谔方程(NLSE)为理论模型,利用分步傅里叶计算方法,研究了输入脉冲的中心频率和脉宽对中红外超连续谱(SC)的影响。采用的微结构硫化物光纤具有较高的非线性效应和两个零色散波长(ZDW),且第二个零色散波在中红外波段,有利于中红外超连续谱的产生。通过仿真发现,输入脉冲的中心频率和脉宽对连续谱的产生都有很大影响。数值仿真中,输入具有不同频率和脉宽的脉冲,输入波长接近零色散点时较远离色散点时产生的中红外超连续谱要宽。而且,在保持峰值功率不变的情况下,脉宽对频谱展宽程度没有影响,但是较短脉冲产生的中红外超连续谱更为平坦。     

色散平坦渐减光纤中超连续谱产生的特性研究

理论研究了色散平坦渐减光纤中超连续谱的产生。研究结果表明，光纤的色散特征对光脉冲的传输和超连续谱的产生有重要影响。由于住泵浦波长处光纤的色散斜率为零，因此脉冲在光纤中传输时保持对称，并产生对称的超连续谱。光纤的色散曲线越平坦，色散曲线的两个零色散波长相距就越远，越有利于超连续谱的展宽。     

三零色散光子晶体光纤中超连续谱的产生与控制

提出了利用倍频效应得到双波长抽运三零色散光子晶体光纤(PCF),产生近红外、中红外波段超连续谱。设计三零色散光子晶体光纤结构,采用分步傅里叶算法数值求解非线性薛定谔方程,模拟双波长抽运三零色散光子晶体光纤产生超连续谱的演化过程,分析了不同光纤长度和脉冲峰值功率对产生的超连续谱的影响。结果表明:当抽运激光脉冲中心波长分别为1μm和2μm、脉宽为100 fs、重复频率为200 k Hz,传输距离为10 cm、脉冲峰值功率为10 k W时,得到了谱宽为690~3150 nm的超连续谱,包含了近红外、中红外波段,光谱具有较好的连续性和平坦度。     

光子晶体光纤产生紫外超连续谱的数值研究

提出了一种基于高非线性氟化镁光子晶体光纤产生紫外超连续光源的方法。采用分步傅里叶法求解光纤的非线性薛定谔方程,基于光子晶体光纤数值模拟了扩展到紫外波段的超连续谱的产生;通过分析光纤结构参量与泵浦光源参数对紫外超连续谱产生的影响,得出了光纤长度、色散参量以及泵浦脉冲峰值功率、初始脉冲宽度对超连续谱光谱宽度的影响规律。研究发现:当光子晶体光纤长度为8 cm、脉冲中心波长为450 nm、峰值功率为3.1 kW、初始脉冲宽度为40 fs时,可获得展宽至紫外的超连续谱,范围为279.6～769.0 nm。     

利用正常色散微结构光纤产生平坦的超连续谱

利用1.7 ps、中心波长为1565 nm和重复率为10 GHz光脉冲入射到80 m具有小正常色散的色散平坦高非线性微结构光纤(HNL-MF)中,在通信波段获得平坦展宽超过100 nm的超连续谱.除了在泵浦波长附近几nm波长范围内具有小的谱峰外,超连续谱在1 512～1 612 nm内具有±3 dB的平坦度.同时研究了不同泵浦波长情况下超连续谱产生的情形,由于不同泵浦波长处光纤的色散斜率不同,因此对超连续谱对称性产生一定的影响,色散斜率越小,产生的谱的对称性也越好.     

色散光纤中超连续谱的产生及多波长输出

超短脉冲在高非线性光纤中传输过程遵循非线性薛定谔方程,因此可通过分步傅里叶变换的方法对此过程进行数理模拟和分析。借用MATLAB工具软件产生一个高斯皮秒脉冲,研究脉冲通过色散光纤之后频谱得以展宽,从而能够通过阵列波导光栅(AWG)进行分波之后得到多波长输出的超连续谱。结果表明:使超连续谱频谱得以展宽的因素有很多,其中群速度色散值对其影响较为显著。对光纤及脉冲的各参数进行优化调节之后,再对色散参量D0进行微调,超连续谱将得到更好地修整优化,频谱变得更宽且平坦稳定。     

基于级联调制器抽运源的1.7μm波段宽带光源

设计实验实现了基于级联调制器抽运源的1.7μm波段宽带光源。采用连续光源和级联调制器组合的方式,在反常色散区域抽运1 km的高非线性色散位移光纤,产生了超连续谱。经过光纤波分复用器的滤波后,得到了峰值波长为1748.9 nm、输出功率约为22 dBm、20 dB光谱范围为1.6~2μm、相应的谱宽约为419 nm的宽带光源。通过增加Sagnac滤波器,得到了频率周期为2.5 nm、强度周期为9.5 dB的多波长宽带光源。此外,分析了抽运功率、波长及重复频率对超连续谱展宽的影响。     

抽运波长对中红外超连续谱影响的数值模拟

采用数值模拟研究了飞秒脉冲在悬吊芯As_2S_3微结构光纤中传输时,抽运波长对中红外超连续谱产生的影响。通过分步傅里叶算法数值求解广义非线性薛定谔方程,对不同抽运波长的飞秒脉冲在悬吊芯As_2S_3微结构光纤中传输时的传输特性及演化过程进行分析。模拟结果表明,当抽运波长为2300nm时,处于光纤的反常色散区且近零色散波长,可获得宽带且平坦的中红外超连续谱,光谱范围覆盖1.2~7μm;当抽运波长为2500nm时,处于光纤的反常色散区且远离零色散波长,可获得超宽带中红外超连续谱,光谱范围覆盖1.2~7.5μm,但其平坦度略差。该结果对产生中红外超连续谱时选择合适的激光抽运波长,进而优化中红外超连续谱具有重要的参考价值。     

高非线性光子晶体光纤中超连续谱产生的特性研究

利用数值方法求解广义非线性薛定谔方程,数值模拟了光脉冲在高非线性光子晶体光纤正常色散区超连续谱产生的演化,研究和分析了脉冲参数如峰值功率,脉冲宽度及初始频率啁啾对超连续谱形成的影响.结果表明,当脉冲峰值功率一定时,随着传输距离增大,超连续谱随之愈宽,平坦度愈好;随着脉冲峰值功率逐渐增大,超连续谱随之更宽,平坦度有所劣化.相反,脉冲宽度逐渐增大,超连续谱展宽范围减小,其平坦度也逐渐劣化;具有适当的正负啁啾脉冲,在高非线性光子晶体光纤传输中获得宽而平坦超连续谱.     

色散平坦渐减光纤产生平坦超连续谱的数值研究

通过数值计算，对色散平坦渐减光纤(DFDF)产生平坦超连续谱(SC)进行了研究。结果表明，该光纤中抽运脉冲峰值功率对超连续谱的形成有着重要的影响，超连续谱的产生存在阈值功率，抽运脉冲峰值功率由阈值逐步增大，超连续谱随之愈宽，平坦度愈好，但增大到一定值时，超连续谱的平坦度会开始劣化，综合考虑各因素找到了产生平坦超连续谱的最佳功率；四阶和五阶群速度色散(GVD)是该种光纤产生平坦超连续谱的决定因素，三阶及五阶以上群速度色散的作用可以忽略；进一步研究发现，超连续谱频谱展宽的机理主要来自脉冲的自相位调制效应，自变陡、受激拉曼散射等高阶非线性效应对平坦超连续谱的产生没有显著影响，在计算的时候完全可以忽略。     

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.     

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