一种提高λ/4相移光纤光栅开关性能的方法

基于耦合模理论，利用逆向递推传输矩阵方法，数值研究了光纤光栅透射输出端面存在反射时λ／4相移光栅的开关特性，以及啁啾的引入对其开关性能的影响。研究结果表明：对于反射相干叠加加强，可使λ／4相移光栅的阈值开关能量得到降低，但开关对比度将下降；在λ／4相移光纤光栅中引入负啁啾，能使开关对比度得到较大的提高，但双稳阈值开启能量会增加;引入正啁啾，可进一步降低开关阈值，但开关对比度会下降；啁啾的引入将对λ／4相移光栅的双稳环宽度产生较大影响。     

抗蚀剂组合法制造DFB激光器λ／4相移光栅

本文介绍用正、负光致抗蚀剂组合的方法,制造用于DFB激光器λ/4相移光栅的原理及工艺,并给出了研究结果和质量评价。光栅周期为4600A,相移转换区小于3μm。     

光纤相移光栅阻带中透射窗口位置的确定

利用矩阵方法分析了相移光栅的相移量改变时，阻带中透射窗口位置的变化情形，以及如河改变窗口锐度的问题，并进一步讨论了相移光栅在光波解复系统中的应用，这些理论结果对相移光栅的实际制作及应用有重要的指导意义。     

多相移和级联光纤光栅透射光谱特性研究

基于耦合模理论,利用传输矩阵法,系统地分析了多相移和级联相移光纤光栅的透射谱特点.结果表明,相移光纤光栅可在透射谱阻带中打开一个或多个透射窗口,多个相移时,透射窗口数等于相移的个数.改变相移量的大小可以改变输出光波长,而且随着相移量的增加,多相移和级联情况下,透射窗口向长波方向移动.光栅的级联使得其在布喇格衍射波长处,打开一个极窄的透射窗口,透射率与级联个数有关,当级联数为4时,透射率最高.     

变迹相移光纤光栅传输谱的研究

用传输矩阵法对变迹相移光纤光栅的传输谱进行了分析,着重分析了相移点数、变迹函数的类型对光栅传输特性的影响。分析表明：可以通过改变光栅的相移点数、选择不同的变迹函数,研制用于WDM和DWDM的滤波器。     

相移光纤光栅特性分析

利用传输矩阵法分析了相移光纤光栅的特性,导出了反射率理论表达式,并讨论了光栅反射谱中透射峰与相移量、相移区位置以及光栅的参数的变化关系。     

相移光纤光栅传输谱的研究

相移光纤光栅可作为密集波分复用（DWDM）系统中的解复用器，相移的大小，位置和相移点的多少对该解复用器的性能有重要影响，应用传输矩阵理论分析了相移光纤光栅的相移大小，相移位置不同和多点相移对光纤光栅传输谱的影响。     

基于点测量法的非定步长相移恢复算法

提出了一种新的计算光栅相移量点测量法。利用该方法可精确地计算出光栅相移量,精度达到1nm。该方法抛弃了非定步长算法中利用傅立叶变换获取光栅相移量的方式,使非定步长相移算法在三维曲面形貌测量中的应用进一步趋向完善。     

DFB光纤激光器中相移光栅优化分析

相移光栅在光通信领域具有较高的应用价值,文中用传输矩阵法,详细分析了相移光栅中相移量,折射率调制深度,相移位置及光栅长度对相移光栅的影响,并结合相移光栅在DFB光纤激光器中的应用进行了分析。分析表明,实际制作DFB光纤激光器时,应根据实际应用场合,对相移光栅的相关参数进行设计,从而提高光纤激光器性能。     

相移光栅的特性及其在上下话路复用器中的应用

基于耦合模理论,运用传输矩阵法对相移光栅的透射谱进行了数值计算,着重分析了不同相移量,不同相移位置的单相移光栅的特性;等相移量等间隔的多相移光栅的特性;在此基础上,提出了将相移光栅用于上下话路复用器的结构配置方案,为以后实际应用提供了理论指导和参考.     

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.     

A rigorous proof of MIMO channel capacity’s increase with antenna number

It is well known that adding more antennas at the transmitter or at the receiver may offer larger channel capacity in the multiple-input multiple-output（MIMO） communication systems. In this letter, a simple proof is presented for the fact that the channel capacity increases with an increase in the number of receiving antennas. The proof is based on the famous capacity formula of Foschini and Gans with matrix theory.     

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