高性能2.5Gb／s用的DFB—LD／EA单片集成器件

报导了采用全ＭＯＣＶＤ生长的１．５５μｍ的单片集成ＤＦＢ＝ＬＤ／ＥＡ组件的 在ＤＷＤＭ系统上的传输测试结果，出纤功率Ｐｆ≥２．５ｍＷ＠Ｉｆ＝７５ｍＡ，边模抑制比ＳＭＳＲ〉３５ｄＢ，调制器反向偏压为２．５Ｖ时的消光比为１４ｄＢ，该发射模块在２．５Ｇｂ／ｓＤＷＤＭ系统上进行了传输试验，传输２４０Ｋｍ后无误码，其通道代价≤１ｄＢ＠ＢＥＲ＝１０＾－１２。     

沥青基高比表面积活性碳的物理及化学结构

本文用ＡＳＡＰ２０００吸附仪测定了吸附性能优异的沥青基高比表面积新型活性碳（ＰＨＡＣ）的ＢＥＴ比表面积、用ＢＪＨ和ＤＲＳ法分析了其孔隙结构参数，用ＸＰＳ测定了ＰＨＡＣ的表面元素组成及含氧官能团，对ＰＨＡＣ的表面形态结构进行了ＳＥＭ和ＴＥＭ观察。研究表明：ＰＨＡＣ具有高度发达且均匀的微孔结构，其表面含有一定量的Ｃ－Ｏ－Ｃ、Ｃ－ＯＨ、Ｃ＝Ｏ、Ｏ＝Ｃ－Ｏ等多种类型的含氧官能团。     

CORBA在TMN环境中的应用

在分析了电信管理网（ＴＭＮ）和公共对象请求代理体系结构（ＣＯＲＢＡ）各自特点的基础上，探讨了ＣＯＲＢＡ在ＴＭＮ中的应用，并提出一种新的基于ＣＯＲＢＡ的ＴＭＮ管理平台构想。     

第11届OIML大会和第35届CIML会议在伦敦召开

第１１届国际法制计量组织 (ＯＩＭＬ)大会和第３５届国际法制计量委员会(ＣＩＭＬ)会议于２０００年１０月９日至１３日在伦敦召开。参加会议的代表来自４８个成员国 ,１３个通讯成员 ,１２个其它国际组织和区域法制计量组织。ＯＩＭＬ成员国和通讯成员已由上届的９６个发展到１０５个 ;作为ＷＴＯＴＢＴ委员会的观察员 ,ＯＩＭＬ在推行国际技术标准 ,消除技术壁垒方面发挥了积极作用 ;ＯＩＭＬ还与ＩＳＯ、ＩＥＣ、ＢＩＰＭ、ＩＭＥＫＯ、Ｉ ＬＡＣ等有关国际组织保持了密切合作 ;ＯＩＭＬ建立了与各区域法制计量组织的联系 ;计量器具制造…     

用柠檬酸盐-凝胶法低温合成单相Ba(Mg1/3Ta2/3)O3

本文利用ＸＴＤ、ＤＴＡ、ＴＧＡ、ＳＥＭ、ＴＥＭ等分析手段研究了用柠檬酸盐－凝胶法低温（６００℃）合成单相Ｂａ（Ｍｇ１／３Ｔａ２／３）Ｏ３的方法。结果发现，与传统的固相反应合成ＢＭＴ的方法相比，柠檬酸盐溶胶－凝胶法能在６００℃的温度下合成单相ＢＭＴ，睽怕粉体具有１０￣２０ｎｍ的单颗粒尺寸。     

PAA与PBTCA对CaCO3显微结构的影响

利用扫描电镜(ＳＥＭ)和原子力显微镜(ＡＦＭ)研究了分散剂ＰＡＡ与ＰＢＴＣＡ对ＣａＣＯ _３显微结构的影响．结果表明,与ＰＡＡ相比,ＰＢＴＣＡ对ＣａＣＯ_３的沉积形貌具有更大的影响．ＳＥＭ表明,在两种分散剂的存在下,沉积物的形貌皆发生了变化,随着阻滞影响增大,沉积物晶型畸变程度随之严重,沉积物形貌的分维值也随之增大．ＸＲＤ分析表明,随着阻滞影响增大,ＣａＣＯ_３晶相中球霰石的含量增大．在分散剂存在下,热力学上属亚稳态的文石和球霰石从动力学上被稳定住了．ＡＦＭ研究表明,随着阻滞影响增大,ＣａＣＯ_３晶体表面上台阶间距变大．同时,发现了ＣａＣＯ_３晶体表面台阶的聚并现象并进行了讨论．     

一种用于热校准风洞的数据采集系统集成及软件设计

简要介绍了研华ＡＤＡＭ４０００系列模块的性能及其特点，并详细阐述了利用该系列模块组成一种用于热校准风洞的数据采集秕 及ＬＡＢＴＥＣＨＣＯＴＲＯＬ组态软件包在整个中的应用。     

掺杂BaCeO3和SrCeO3在氧,氢及水气气氛下的电导性能

掺杂碱土金属铈酸盐系统：ＭＣｅ１－ｘＲｘＯ３－ｘ／２（Ｍ＝Ｂａ，Ｓｒ；Ｒ＝Ｙｂ，Ｙ，Ｇｄ，Ｌａ；ｘ＝０．０１～０．１０）可由固相反应制得单相化合物，Ｘ射线衍射分析表明，掺杂元素及掺杂量对掺杂ＢａＣｅＯ３和ＳｒＣｅＯ３的晶体结构影响不大。用复数阻抗谱研究了在氧、氢、水气气氛下的电导性能。在各种气氛下ＭＣｅ０．９５Ｙｂ０．０５Ｏ２．９７５（Ｍ＝Ｂａ，Ｓｒ）的电导率最大。根据测试结果，结合缺陷化学理论讨     

Na掺杂对MTG-YBCO临界电流密度特性的影响

本文研究了Ｎａ掺杂对ＭＴＧ－ＹＢＣＯ（ＹＢａ２－ｘＮａｘＣｕ３Ｏｙ＋４０ｍｏｌ％Ｙ２ＢａＣｕＯ５ｘ＝０．０、０．１、０．２）生长织构及其超导性能的影响。适量Ｎａ的掺入有利于ＭＴＧ－ＹＢＣＯ沿（ａｂ）面的生长,改善晶体生长的宏观形貌。同时,掺Ｎａ后ＭＴＧ－ＹＢＣＯ试样的Ｔｃ,ｏｎ变化不大,但Ｔｃ,ｏｆｆ随掺杂量ｘ的增加而降低,即超导转变宽度△Ｔ增大。适量Ｎａ掺杂改善了ＭＴＧ－ＹＢＣＯ的临界电流密度特     

双酚A型氰酸酯树脂的性能

首先对自行合成的双酚Ａ型氰酸酯（ＢＣＥ）树脂进行了ＤＳＣ分析,得到该树脂的熔点为７９．２℃。继而,研究了ＢＣＥ树脂固化后的力学性能。借助ＤＭＡ、ＴＧＡ等热分析技术研究了该树脂固化物的耐热性能。研究结果表明,ＢＣＥ树脂固化的具有优异的耐热性能（Ｔｇ＝２５８℃,起始分解温度〉４２６℃）,较高的力学性能（σｆ＝１０４ＭＰａ,Ｅｆ＝３．１０ＧＰａ,σｃ＝８６ＭＰａ,Ｅｃ＝３．０３ＧＰａ）,良好的耐湿热性能     

TM and TE propagating modes of photonic crystal waveguide based on honeycomb lattices

The waveguide based on the honeycomb photonic crystal has propagating modes for both the TE and TM polarizations. The group index-normalized frequency curves are U-shaped for the two polarizations. The average group index of the TE mode is approximately 3, while the average group index of the TM mode is over 10, which implies that the TM mode is a slow light mode. With the shift value 0 ≤ δx ≤ 0.025a, the group index is over 10 and the normalized delay-bandwidth product is from 0.316 to 0.349, which is ideal for the slow light mode of the TM polarization. In the group velocity dispersion of the waveguide, there is a very large "zero" dispersion region for both the TM and TE modes, which is far larger than that of other photonic crystal waveguides. The TM mode of this kind of waveguide structure is a slow light mode with wide bandwidth and a large "zero" dispersion region.     

Integrated optical polarization splitter based on photobleaching-induced birefringence in azo dye polymers

An integrated optical polarization splitter has been fabricated by utilizing the photobleaching-induced birefringence in an azo dye polymer. It consists of a Y-branch waveguide formed by the reactive ion etching with one of the two arms photobleached. The refractive index of the photobleached arm is decreased for the TE mode and increased for the TM mode. The performance of the splitter was measured as a function of the energy of the photobleaching beam and compared to a wave propagation simulation of the device. The measured cross talks are less than -28 dB for the TM mode and -24 dB for the TE mode at a wavelength of 1310 nm. The measured excess losses for the TE and TM modes, which measure the effect of the Y branch and the photobleaching, are 0.3 and 0.4 dB, respectively. The insertion loss was 5 dB, which includes the input fiber to waveguide coupling loss.     

Polarization dependent solar cell conversion efficiency at oblique incident angles and the corresponding improvement using surface nanoparticle coating

Despite tremendous efforts on improving the solar cell conversion efficiency at normal incidence, improvement at oblique angles has not been widely addressed, not to mention the corresponding light absorption behaviors at different polarizations. Here we report the characterization of the solar cell conversion efficiency and the spectra of photoresponsivity at various tilted angles. The results show that TM (transverse magnetic) polarized light possesses higher photoresponsivity than TE (transverse electric) polarized light and the difference becomes larger with the incidence angle. To address the issue, a monolayer of silica nanoparticles on the solar cell surface was employed to improve the light absorption. Even though both TE and TM waves show a decrease in the surface reflectivity with the presence of nanoparticles, the interaction between the silica particles and the TE wave is more significant. The improvement of the conversion efficiency for obliquely incident light is explained from the refractive index difference of the nanoparticles for the TE and TM polarizations.     

Microwave absorbers of two-layer composites laminate for wide oblique incidence angles

Advanced microwave absorbers for wide oblique incidence angles are required in many applications including wireless communication or vehicle identification in Intelligent Transport System (ITS) where 5.8 GHz Dedicated Short Range Communication (DSRC) system is applied. In this study, two-layer microwave absorbers are designed for the achievement of low reflection coefficient over wide incidence angles at 5.8 GHz. The absorbing layer of rubber composite containing magnetic iron flake particles and the surface layer of low dielectric constant (carbon black composite and glass fiber composite) have been used in the absorber design. On the basis of transmission line theory, the reflection loss has been calculated with variation of incident angles for both Transverse Electric (TE) and Transverse Magnetic (TM) polarization. At the optimum thickness of the composite layers, a low value of reflection loss (less than −10 dB) has been predicted for wide incidence angles up to 60° for both TE and TM polarization, which is well consistent with the reflected power measured by free-space arch test. The two-layer composite laminate consisted of magnetic absorbing layer with high magnetic and dielectric loss and surface impedance-matching layer of a controlled dielectric constant can be proposed for high potential microwave absorbers in ITS.     

Ka波段TE01模回旋行波管宽带输入耦合器的设计

Ka波段TE01模回旋行波管的输入耦合器将矩形波导中输入的TE10模转化为圆波导中TE01模的行波场,以实现对回旋电子注角向速度的调制。本文首先对Ka波段TE01模回旋行波管的输入耦合器进行了解析分析和数值计算。通过数值计算得到输入耦合器的初步结构和尺寸,然后利用三维高频分析软件HFSS进行精确的模拟和修正。通过优化设计在Ka波段获得了3 dB带宽约为3 GHz,1 dB带宽大于2GHz的高性能TE1□0-TE4◎11-TE0○1输入耦合器和3 dB带宽约为3.5 GHz,1 dB带宽约为3 GHz的高性能TE1□0-TE5◎11-TE0○1输入耦合器。冷测实验研究表明优化设计结果与冷测结果相吻合。     

渐变折射率光波导模场分布的矢量FD-TD法分析

用二维矢量时域有限差分法分析了渐变折射率光波导中基模的模场分布情况，采用平面光波，球面光波，高斯光波等五种不同形态的光波激励同一波导，借助计算机进行数值求解，得到的光场分布图在光场传播达到稳定后完全相同，说明了波导的模式与光波形态无关，只与波导结构和光波波长有关，结果直观，精确，快速，并与解析法分析的结果相一致。     

Efficient Single-Mode GaAs/AlGaAs W Waveguide Phase Modulator with a Low Propagation Loss

We report a single-mode P-P-p-i-n-N-N GaAs/AlGaAs W waveguide phase modulator with a high phase modulation efficiency and a low propagation loss. The phase modulator with a W-shaped refractive-index profile utilizes a novel epilayer structure to reduce the propagation loss associated with doped layers and to obtain a phase modulation efficiency larger than those of P-i-N double heterostructure modulators. The phase shift and propagation loss were measured with a Fabry-Perot resonance method at 1.31-mum wavelength. A phase modulation efficiency as high as 34.6 degrees /V mm was measured for TE polarized light. Also propagation losses of less than 0.6 dB/cm were achieved. As a result, the W waveguide phase modulator that exhibits a high phase modulation efficiency and a low propagation loss have been experimentally realized for the first time as far as we know.     

Nonlinear analysis of a photonic crystal laser

An approximate nonlinear analysis of light generation in two-dimensional square- and triangular-lattice photonic crystal lasers including gain saturation effects is presented for the TE modes. This model extends earlier studies which took into account only TM modes. Our approach is based on coupled mode theory. With the help of an energy theorem and a threshold field approximation an approximate formula relating the small signal gain required to obtain a given output power to the structure parameters has been obtained. It has been used to calculate laser characteristics revealing an optimum coupling strength for which laser structure achieves maximum power efficiency.     

Heat-resistant flexible-film optical waveguides from fluorinated polyimides

Heat-resistant flexible-film optical waveguides were fabricated from fluorinated polyimides. These waveguides operated in single mode and had low optical loss (0.3 dB/cm) at a wavelength of 1.3 mum for TE and TM polarizations. They also had good flexibility: The optical loss did not significantly change above a minimum radius of curvature of less than 20 mm. The birefringence of 9 x 10(-5) between the TE and TM polarizations is 2 orders of magnitude smaller than that for a waveguide upon a substrate. Moreover, these waveguides had high thermal stability and moisture resistance: The optical loss and single-mode behavior changed little after heating the waveguides at 420 degrees C for 1 h or after their exposure to 85% relative humidity at 85 degrees C for more than 350 h.     

Antireflection structures with use of multilevel subwavelength zero-order gratings

It is known that the zero-order two-phase-level gratings with a period much smaller and a thickness much larger than the wavelength may have antireflection properties the same as appropriate dielectric layers under normal incidence. On the basis of the rigorous coupled-wave analysis method formulation, it is shown that multilevel unidimensional phase gratings, for both TE and TM polarization, are functionally equivalent to antireflection structures of multilevel dielectric layers, even if the period is close to the wavelength.