反向多抽运光纤拉曼放大器偏振相关增益研究

基于光纤拉曼放大器(FRA)的非线性耦合方程,采用数值计算的方法系统研究了反向多抽运FRA中的偏振相关增益(PDG),其中包括FRA系统中由所有光波拉曼相互作用所产生的PDG、由抽运-信号拉曼相互作用所产生的PDG、由抽运-抽运拉曼相互作用所产生的PDG以及由信号-信号拉曼相互作用所产生的PDG。研究结果表明,相比于单抽运FRA系统,多抽运FRA系统不仅可以获得较平坦的拉曼增益谱而且可以使整个增益带宽内的PDG较均匀。此研究不仅可以有效地估计反向多抽运FRA系统中分别由抽运-信号、抽运-抽运、信号-信号之间拉曼相互作用所产生的PDG,而且对有效降低FRA系统中的PDG提供重要的参考价值。     

同向与反向抽运光纤喇曼放大器的阈值比较

为分析同向抽运与反向抽运光纤喇曼放大器的阈值特性,基于已有的耦合微分方程,采用龙格库塔算法和打靶算法,数值模拟同向抽运和反向抽运光纤喇曼放大器中信号光功率沿光纤的演变过程,在此基础上根据实际情况推导出同向与反向抽运光纤喇曼放大器的阈值公式,这些公式比文献中的阈值公式更全面。然后,详细分析各个参数对同向抽运和反向抽运光纤喇曼放大器阈值特性的影响,并且对两种抽运方式的阈值进行比较,结果表明,各参量对同向和反向抽运FRA的阈值影响有相同的地方,也有不同的地方。相同参数时,反向抽运光纤喇曼放大器的阈值都大于同向抽运光纤喇曼放大器的值。结论对于光纤喇曼放大器的优化设计和实验有指导作用,为进一步的研究提供有益的参考。     

抽运功率配置对双向拉曼放大器功率转换效率的影响

为了对分布式双向抽运光纤拉曼放大器的功率转换效率进行研究,在不同的抽运功率配置条件下,采用打靶法和龙格库塔法相结合的数值算法,由耦合方程出发,详细分析不同物理因素对双向抽运光纤拉曼放大器功率转换效率的影响,包括增益、增益饱和、初始信号光功率以及总的抽运功率。结果表明:信号较小、总的抽运功率较小时,抽运功率配置对双向抽运光纤拉曼放大器效率的影响较小。信号较大、总的抽运功率较大时,抽运功率配置对双向抽运光纤拉曼放大器效率的影响显著;双向抽运FRA的功率转换效率随着同向抽运功率占抽运总功率百分比的增加而增加。所得结论有新的进展,对双向抽运光纤拉曼放大器和光纤拉曼放大器功率转换效率的进一步研究有重要参考意义。     

抽运功率配置对双向喇曼放大器性能的影响

为了研究抽运功率配置对双向抽运光纤喇曼放大器性能的影响,基于已有的耦合方程,采用数值仿真方法,分析了不同抽运功率配置对双向抽运光纤喇曼放大器的增益、增益饱和以及抽运功率转换效率的影响。结果表明,双向抽运光纤喇曼放大器的增益、增益饱和以及抽运功率转换效率特性均介于同向和反向抽运光纤喇曼放大器之间,并且随着同向抽运功率在抽运总功率中所占比例的升高,增益、增益饱和功率和抽运功率转换效率的数值增加;大信号、抽运功率较大时,抽运功率配置对双向抽运光纤喇曼放大器性能的影响显著。这对双向抽运光纤喇曼放大器和光纤激光研究具有一定的参考价值。     

光纤拉曼放大器的最大拉曼增益特性

为了分析同向抽运与反向抽运光纤拉曼放大器的最大拉曼增益,基于耦合微分方程,采用理论推导的方法,根据不同抽运结构下信号光放大的不同实际情况定义并推导出同向抽运光纤拉曼放大器和反向抽运光纤拉曼放大器的最大拉曼增益公式。然后,详细分析了各个参数对两种抽运方式下光纤拉曼放大器的最大拉曼增益的影响。对两种抽运方式下相同参数引起的最大拉曼增益进行了比较。结果表明,同样的参数对同向抽运与反向抽运光纤拉曼放大器最大拉曼增益的影响有相同的地方,也有不同的地方。最后,将最大拉曼增益和常用的开关增益进行了比较。对光纤拉曼放大器的实验、成本估计和器件效率等研究有重要参考意义。     

反向抽运光纤拉曼放大器偏振相关增益的数值计算

基于反向抽运方式的光纤拉曼放大器(FRA)的非线性耦合方程,采用数值计算的方法首次系统研究了单抽运多信号传输的FRA系统中各因素——光纤偏振模色散(PMD)、抽运光输入功率、抽运光波长、信号光输入功率、光纤长度及光纤损耗系数等对由抽运-信号拉曼相互作用所产生的偏振相关增益(PDG)的影响;比较了单抽运多信号FRA系统与单抽运单信号FRA系统中由抽运-信号拉曼相互作用所产生的PDG的大小;总结了各参数对降低由抽运-信号拉曼相互作用所产生的PDG的效果。研究结果表明,单抽运多信号FRA系统中的PDG主要由抽运-信号拉曼相互作用产生,并且光纤的PMD值和抽运光功率对PDG的影响较明显。     

抽运方式对耗散孤子光纤激光器性能的影响

基于扩展的标量非线性薛定谔方程,理论研究了不同抽运方式对正色散腔被动锁模掺镱光纤激光器输出特性的影响。结果表明,在初始总增益相同条件下,对于给定的增益饱和能量,反向抽运时耗散孤子的光谱宽度和脉冲宽度均比正向抽运时小,而对应的脉冲峰值功率比正向抽运时高,并且反向抽运时脉冲的啁啾线性拟合度相比正向抽运时低。当增益饱和能量相同时,正、反向抽运获得的耗散孤子的能量相等,但两种抽运方式下耗散孤子的光谱和时域波形的差异程度随增益饱和能量的增加而增大。     

同向抽运光纤拉曼放大器功率转换效率的理论分析

为了对同向抽运光纤拉曼放大器的功率转换效率进行研究,由耦合方程出发,首先理论推导出功率转换效率的解析解,然后采用数值计算的方法详细分析不同物理因素对功率转换效率的影响。结果表明：功率转换效率先随着光纤长度和单位面积的拉曼增益系数增加而增加,当增加到最大值时保持数值不变;小信号时,初始信号光功率对功率转换效率的影响较小;大信号时,功率转换效率随着初始信号光功率增加而快速增加;功率转换效率和初始抽运光功率呈抛物线曲线关系;抽运光与信号光的频率比增加时,功率转换效率减小。     

宽带FRA中多波长抽运功率的自动优化方法

采用平均功率分析算法,数值求解多抽运宽带拉曼光纤放大器(FRA)增益过程的功率耦合方程;利用遗传算法强大的数值搜索能力,对10波长抽运FRA的抽运光进行功率优化;获得了80nm带宽,增益波动低于0．4dB的结果。     

同向抽运光纤拉曼放大器的阈值特性

为全面分析同向抽运光纤拉曼放大器的阈值特性,基于耦合微分方程,采用龙格库塔算法,数值模拟同向抽运光纤拉曼放大器中信号光功率沿光纤的演变过程,在此基础上根据实际情况推导出同向抽运光纤拉曼放大器的阈值公式。然后,数值计算各个参数对同向抽运光纤拉曼放大器阈值特性的影响,结果表明,初始信号光功率、光纤有效长度、拉曼增益系数、抽运光和信号光频率比值增加,阈值减小;光纤有效面积越大,阈值越大。     

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