均分直槽微结构光纤光栅磁场传感器

对微结构光纤磁场传感器的增敏性能进行研究, 设计了一种基于飞秒激光微加工的均分直槽型微结构光纤磁场传感器。 利用飞秒激光在刻有光纤布拉格光栅(FBG)的单模光纤(SMF)包层上刻蚀均分直槽微结构, 并采用HF溶液清除直槽内的残留碎屑和 应力集中点,随后用磁控溅射技术在加工部位溅射一层磁致伸缩薄膜TbDyFe。当外界磁 场强度变化时,通过观测传感器中心 波长的变化可实现对磁场强度的测量。直槽微结构能减小光纤横截面积,改善光纤轴向伸缩 性能,增大薄膜附着表面积,从而 提高传感器探头灵敏度。理论分析了直槽微结构提高传感器性能的工作原理,介绍了传 感器探头的制备工艺和性能影响因 素,给出了不同参数传感探头的磁场测试结果。实验结果表明,利用飞秒激光加工直槽微结 构能明显改善传感器探头灵敏度, 其中直槽个数对性能影响最为明显;相对于无微结构传感器探头,有微结构光纤探头灵敏度 最高可提升3.8倍。     

新型高灵敏长周期光纤光栅溶胶凝胶气敏传感器

通过在长周期光纤光栅包层外涂覆一层溶胶凝胶气敏薄膜,设计了一种新型高灵敏光气敏传感器,折射率分辨率高达10-8.研究了传感器灵敏度随薄膜参数与光栅参量的变化关系,给出了高灵敏度所需的最佳参数设计范围.实验上成功制作了镀膜光纤光栅乙醇传感器.     

光纤光栅温敏特性研究

分析了光纤光栅（FBG）的温度特性、温度补偿和温度增敏原理,实验研究了温度特性、温度的补偿及增敏。实验结果表明：光纤光栅对温度的改变呈现出良好的线性；所采用的补偿装置在测试范围内基本能消除温度对光纤光栅Bragg波长的影响；采用实验所用的增敏装置，可以将光纤光栅的温度灵敏度提高9.3倍。     

高灵敏度长周期光纤光栅温度传感器的研究

采用纤芯弹光系数大于包层弹光系数的长周期光纤光栅,且在其包层外面涂覆一层随温度升高折射率减小的薄膜材料,同时采用线膨胀系数较大的金属封装光栅等三种增敏措施,可提高长周期光纤光栅温度传感器的灵敏度,测得其灵敏度系数为0.237 5 nm/℃,温度分辨率小于0.1 ℃.     

基于逐点法刻写的偏芯光纤布拉格光栅应变和温度传感研究

为解决当前光纤光栅制备灵活性较低,以及测量 中不利于实现分布式波分复用的问题,提出了一 种于基于逐点法刻写的偏芯光纤布拉格光栅传感器(eccentric fiber Bragg grating,EFBG)。采用飞秒激光(femtosecond laser,FSL)逐 点刻写技术,光栅刻写位置垂直偏离光纤中心3 μm,光栅长度为5 mm,光栅中心波长为1 633 nm。不 同于传统光纤光栅,偏芯结构的光栅可以激发出较宽的包层模共振范围,通过分析包层模共 振峰的波长 漂移量,表征施加的应变大小或温度高低。实验结果表明,应变测量范围在0—5 00 με时,包层模灵敏度为 0.98 pm/με,温度测量范围在30—80 ℃时, 包层模灵敏度为10.89 pm/℃,并且包层模灵敏度相比芯模灵敏 度数值相差较小,从而可以实现应变或温度的传感测量。     

增敏型级联双参量测量的光纤传感器北大核心CSCD

旨在有效解决液体折射率检测中温度和折射率交叉敏感的问题,研制了一种增敏型光纤光栅(FBG)级联马赫-曾德尔(M-Z)结构的温度、折射率双参量测量的光纤传感器。通过多次熔接实验,调节相应参数将单模光纤(SMF)和薄芯光纤(TCF)进行拉锥熔接;然后在TCF的另一端熔接无心光纤(NCF),制备出M-Z光纤干涉仪;再在NCF末端级联上铝制毛细管增敏封装后的光纤光栅(FBG),最终完成双参量测量的光纤传感器的制备。根据M-Z干涉原理及FBG模式理论,计算了增敏FBG理论的温度灵敏度,给出了传感器的灵敏度系数矩阵与温度、折射率与透射谱的波长漂移量的理论公式。搭建了温度、折射率传感测试系统,实验结果表明:在15~85℃温度范围内,随着温度增加,该传感器的透射谱逐渐红移,封装后的FBG和M-Z结构的温度与波长偏移量线性相关系数分别为0.96323和0.91577,温度灵敏度分别为33.71 pm/℃和11.58 pm/℃;在室温下(25℃),液体折射率在1.333RIU~1.34235RIU范围内,随着折射率增加,FBG透射谱不发生偏移,M-Z透射谱逐渐蓝移,折射率与波长偏移量线性相关系数分别为0和0.98761,折射率灵敏度分别为0 nm/RIU和-493.51322 nm/RIU。该传感器可以有效提高温度、折射率的检测精度和灵敏度,可应用于环境、生物、石油化工和食品生产等领域。     

含涂覆层长周期光纤光栅温度特性研究

提出在含涂覆层的标准通信光纤中用800nm红外飞秒激光直接写入了长周期光纤光栅（LPFGs）。从理论上分析了光纤涂覆层对于纤芯基模和包层模有效折射率的影响,并进一步研究涂覆层对LPFGs温度灵敏度的影响。分别对制作的去除涂覆层和含涂覆层LPFGs的低阶包层模进行了温度特性实验。结果表明：涂覆层的存在不仅能成为LPFGs理想的保护层,更重要的是将LPFGs的温度灵敏度提高到0.1173 ,与理论分析吻合。这种含涂覆层光纤光栅若作为温度传感器,将有着良好的机械强度和温度灵敏度。     

飞秒激光烧蚀长周期光纤光栅的高温特性研究

为了探索包层去除型长周期光纤光栅的高温传感特性,利用中心波长为800 nm,脉冲宽度为120 fs的飞秒激光烧蚀直写而成并对其进行高温传感检测。首先,通过两块轴线互相垂直的柱透镜将入射激光聚焦成细长焦线,并借助垂直方向CCD成像系统精确定位光纤与焦点的相对位置;然后,通过激光器内嵌shutter与运动平台的耦合控制,实现光纤光栅的精确去除加工;最后,将写制的光纤光栅置于800℃的高温炉中放置2 h。利用高温管式电热炉对所加工光纤光栅在30~1100℃内进行温度传感测试,发现其在30~300℃内谐振波长的温度灵敏度为51 pm/℃,线性度为0.956;但在高温段300~1100℃内,其温度灵敏度达到了135pm/℃,线性度高达0.999。实验结果表明,这种通过包层表面定量去除的长周期光纤光栅更适用于高温及超高温环境的传感检测。     

导模共振滤光片表面镀膜对其物理特性的影响

为了研究亚波长光栅表面上薄膜的生长特性,以及镀膜对亚波长光栅物理特性的影响,对亚波长正弦槽形光栅表面上镀的Au膜进行了实验研究和理论分析.实验发现,当光栅槽深为80 nm,Au膜为100 nm时,薄膜的生长是仿形生长,光栅的正弦槽形特征和周期都基本没有发生变化,但镀膜后,出现光栅的正弦占空比增加、槽的深度减小以及槽深的均匀性变差等现象.对引起这种现象的原因进行了分析.提出了由于光栅微结构而给薄膜生长带来的阴影效应现象,并分析了正弦占空比增加对导模共振滤光片光谱特性的影响.     

FBG温度灵敏度及增敏技术研究进展

研究了光纤布拉格光栅（FBG）的温度传感机理及特征参数对温度灵敏度的影响.针对国内外光纤光栅温度增敏研究的几大方向,分别从光纤光栅的材料选择、写入方法、封装材料和封装工艺等方面,进一步详细分析了光纤光栅温度传感器增敏技术的发展趋势.     

Technology innovation and process integrations for sub-100nm gate patterning

This paper presents a brief overview of the Applied Centura(R)DPS(R)system,configured with silicon etch DPS Ⅱ chamber, with emphasis on discussing tuning capability for CD uniformity control. It also presents the studies of etch process chemistry and film integration impact for an overall successful gate patterning development. Discussions will focus on resolutions to key issues, such as CD uniformity, line-edge roughness, and multilayer film etching integration.     

White organic light-emitting devices based on fac tris（2- phenylpyridine） iridium sensitized 5,6,11,12-tetraphenylnap -hthacene

We have fabricated the white organic light-emitting devices （WOLEDs） based on 4,4＇ -bis（2,2 -diphenyl vinyl）-1,1＇ - biphenyl （DPVBi） and phosphorescence sensitized 5,6,11,12,-tetraphenylnaphthacene （rubrene）. The device structure is ITO/2T-NATA （20 nm）/NPBX （20 nm）/CBP： x%Ir（ppy）3：0.5% rubrene （8 nm）/NPBX （5 nm）/DPVBi （30 nm）/Alq（30 nm）/LiF（0.5 nm）/A1. In the devices, DPVBi acts as a blue light-emitting layer, the rubrene is sensitized by a phosphorescent material, fac tris （2-phenylpyridine） iridium [Ir（ppy）3], acts as a yellow light-emitting layer, and N,N＇ -bis- （1-naphthyl）- N,N＇ -diphenyl -1, 1＇ -biphenyl-4,4＇ -diamine （NPBX） acts as a hole transporting and exciton blocker layer, respectively. When the concentration of Ir （PPY）3 is 6wt%, the maximum luminance is 24960 cd/m^2 at an applied voltage of 15 V, and the maximum luminous efficiency is 5.17 cd/A at an applied voltage of 8 V.     

Complete approach to automatic identification and sub-pixel center location for ellipse feature

To meet the need of automatic image features extraction with high precision in visual inspection, a complete approach to automatic identification and sub-pixel center location for similar-ellipse feature is proposed. In the method, the feature area is identified automatically based on the edge attribute, and the sub-pixel center location is accomplished with the leastsquare algorithm. It shows that the method is valid, practical, and has high precision by experiment. Meanwhile this method can meet the need of instrumentation of visual inspection because of easy realization and without man-machine interaction.     

小角度扩展相关性近似算法分析

本论文提出一种在多天线MIMO信道相关性建模中小角度扩展近似理论算法,并应用于分析MIMO系统性能。分析中分别对三种不同角能量分布情况下的空间相关性研发快速近似计算法,并同时提出双模(Bi-Modal)角能量分布情况下的近似运算。通过分析这些新方法的近似效率,可以得到计算简单、复杂度低、而且符合实际的MIMO相关信道矩阵,对系统级的快速高效计算法的研究和系统级的评估以及误差分析具有重要的意义。     

A Versatile Mixed-Signal Pin Approach for Cost-Effective Test of Automotive ICs

Integrated circuits (ICs) intended for increasingly sophisticated automotive applications bring unique test demands. Advanced ICs for applications such as highly integrated automatic braking system (ABS) and airbag controllers combine high voltage digital channels, significant VI demands and precise timing capability. Along with continued missioncritical reliability concerns, the trend toward higher voltage operation and increased device integration requires specialized test capabilities able to extend across the wide operating ranges found in automotive applications. Among these capabilities, automotive test requirements increasingly dictate a need for a cost-effective versatile mixed-signal pin electronics with very high data rates reaching up to 50MHz with a voltage swing of-2 V to +28 V.     

Optical vibration and deviation measurement of rotating machine parts

It is of interest to get appropriate information about the dynamic behaviour of rotating machinery parts in service. This paper presents an approach of optical vibration and deviation measurement of such parts. Essential of this method is an image derotator combined with a high speed camera or a laser doppler vibrometer （LDV）.     

INTEGRATION OF OPTICAL AND WIRELESS NETWORKS

正For a long time,optical and wireless systems/net-works are developed in separate communities witha few attempts for in-depth convergence.In fact,it prom-ises many advantages to combine the optical and wire-less technologies in the levels of systems and networks.Recently,both academia and industry have made manyefforts to enter a new phase of development to take op-tical and wireless systems as fully integrated networks.To provide high bandwidth and reliable service for bothfixed and mobile users,a well-designed network must     

社长序言（英文）

正Happy New Year!As we step into a new year,we take a look back at the key feature topics covered in China Communications over the past 12 months and set out our expecta-     

云计算专题（英文）

正Cloud computing is a novel computing paradigm that utilizes remote cloud resources to achieve a high-performance computation.Cloud provides infrastructure,platform and software as different on-demand services.China has made remarkable progress in cloudbased products and operating system technology.The government,enterprises and research institutions are all active in the development of cloud computing-related projects.Despite the progress,many important problems     

Call for Papers—Feature Topic,Vol.12,No.3,2015

正Smart Grid Communications The electric power industry is undergoing profound changes as the industry aims to capture the promise of a smart grid for a sustainable energy future.Enabled by the advanced sensing devices such as Phasor Measurement Units(PMUs),increasingly powerful