1.48μm泵浦EDFA的研制及其在模拟光纤传输系统中的应用

利用国产１．４８μｍ泵浦ＬＤ和优质掺饵光纤研制了一种实用化的掺饵光纤放大器，小信号净增益２８ｄＢ，噪声系数５．１ｄＢ，增益谱宽大于２０ｎｍ，最大输出功率达４．８ｄＢｍ和１１ｄＢｍ。实验研究了ＥＤＦＡ在ＦＭ／ＦＤＭ模拟电视光纤系统的应用，利用ＥＤＦＡ作为系统的功率提升和中继放大器，分别成功地进行了１８５ｋｍ和２２４ｋｍ的系统传输试验。     

DBM-g-PE与PVC的相互作用研究EI

采用固相接枝法制备了ＤＢＭ－ｇ－ＰＥ，用红外光谱分析证明了接枝物确实存在。ＰＶＣ／ＣＰＥ＝１００／５合金性能测定结果表明，添加５份接枝物的合金（Ａ），缺口冲击强度、拉伸强度分别为１８．２ｋＪ／ｍ２和５３．０ＭＰａ；而添加５份ＰＥ的合金（Ｂ），其相应性能为５．１ｋＪ／ｍ２和３３．８ＭＰａ。不加接枝物的合金（Ｃ），虽有高韧性，但拉伸强度却由５３．０ＭＰａ降至５０．２ＭＰａ。ＤＳＣ、ＳＥＭ的结果均表明，ＰＥ接枝ＤＢＭ后与ＰＶＣ的相互作用增强，与ＣＰＥ协同作用能增韧、增强ＰＶＣ，并探讨了其机理。     

采用DFB＋MZ调制器组件为光源的10Gb／s100kmG.652光纤传输实验研究

报道了运用ＤＦＢ－ＬＤ与Ｍ－Ｚ调制器单片集成组件为光源实现１０Ｇｂ／ｓ１００ｋｍ常规单模光张的传输实验。实验表明,采用光源预啁啾技术可延长系统的传输距离。在误码率ＢＥＲ＝１０＾－１０时,传输后的功率代价为１．１ｄＢ,接收灵敏度为－１６．５ｄＢｍ。这一结果达到了国外同类实验的水平。     

抑制等信道间距陆上干线光纤通信系统中光纤色散和四波混频效应的新方案

提出了一种用以克服等信道间距划分、波分复用（ＷＤＭ）＋掺饵光纤放大器（ＥＤＦＡ）陆上光纤通信系统中光纤色散和四波混频（ＦＷＭ）效应的新方案。采用１５５０ｎｍ处色散为－２．８９ｐｓ／ｋｍ／ｎｍ的小色散单模光纤（ｓｍａｌｌ－ｄｉｓｐｅｒｓｉｏｎｓｉｎｇｌｅ－ｍｏｄｅ－ｆｉｂｅｒ，ＳＤＳＭＦ）可避免严重的ＦＷＭ效应，同时利用ＩＴＵ－ＴＧ．６５２非色散位移光纤（ｎｏｎ－ｄｉｓｐｅｒｓｉｏｎ－ｓｈｉｆｔｅｄｆｉｂｅｒ，ＮＤＳＦ），在ＥＤＦＡ整个带宽范围内（１５３０～１５７０ｎｍ）补偿ＳＤＳＭＦ引入的负色散。采用此方案，一个１０路×１０Ｇｂ／ｓ、１０级ＥＤＦＡ级联的等信道间距（１ｎｍ）光纤通信系统，经近千公里的光纤传输后，ＦＷＭ和色散引入的恶化量将分别小于１ｄＢ。     

109公里2.5Gb／s无中继IM／DD光纤传输实验系统

对国内首次２．４８８Ｇｂ／ｓ光纤传输系统实现结果进行了报道。系统工作波长１５５０ｎｍ，利用常规单模光纤实现了１０９公里无中继传，要用ＩＭ／ＤＤ方式，接收机灵敏度为－３０．５ｄＢｍ．     

亚毫安室温连续工作InGaAs垂直腔面发射激光器

报道了ＩｎＧａＡｓ应变量子讲垂直腔面发射激光器（ＶＣＳＥＬ）的室温连续工作。在ＭＢＥ生长过程中利用红外高温仪测量了表观衬底热辐射振荡，实现了原位厚度监测；采用阶梯型分布布拉格反射器（ＤＢＲ）及腐蚀倒台面结构，降低了器件串联电阻。对于２×３μｍ２的台面结构ＶＣＳＥＬ，室温连续工作阈值电流一般为１．５ｍＡ，最低达到０．７ｍＡ，阈值电压为２．５伏，输出功率达到０．５ｍＷ，激射波长为０．９４ｕｍ，量子效率为１２％。     

波分复用系统中功率代价的测试

介绍了波分复用（ＷＤＭ）系统中功率代价的起因、测试方法和测试顺序,指出了各种起因对系统性能的影响,并提出了减小相应功率代价的方法。给出了８×２．５Ｇｂ／ｓ×（３×１５０ｋｍ常规单模光纤）ＷＤＭ系统中第６信道和第８信道的功率代价测试结果,ＣＨ８的总功率代价为１．８ｄＢ,其中色散代价为０．８ｄＢ,ＡＳＥ代价为０．９ｄＢ,串话代价为０．１ｄＢ;而ＣＨ６的总功率代价则仅有０．６ｄＢ。     

4×155Mb／s频分复用（FDM）光纤通信系统的研究

报道了一个无故障工作时间大于２４小时的四路１５５Ｍｂ／ｓ频分复用（ＦＤＭ）光纤通信系统，实测系统误码率优于０×１０（－１４）。系统接收机包括解复用光滤波器，接收机灵敏度优于－３０ｄＢｍ（ＢＥＲ＝１×１０（－９），频道间距为０．１ｎｍ，四路ＦＤＭ信号－２０ｄＢ的总谱宽为０．７ｎｍ。系统采用国产ＤＦＢ激光器为光源，实际光纤传输距离１８ｋｍ。系统全部实现了脱离光学平台的模块化结构，在长期的系统实验中显示了优良的稳定性。这一成果为ＦＤＭ在光纤传输接入网中的进一步实用化开发铺平了道路。     

RAlO3（R=稀土元素）化合物的结晶学研究

藉助于微机控制的线性扫描系统ＬＳ－１８和ＴＲＥＯＲ、ＰＩＲＵＭ程序对ＳｍＡｌＯ３和ＧｄＡｌＯ３的Ｘ射线射Ｇｕｉｎｉｅｒ－Ｈａｇｇ照相底片数据进行了处理，并精密测定了它们的晶胞参数，ＳｍＡｌＯ３属四方晶系，ａ＝５．２８７６（２）Ａ，ｃ＝７．４８５８（７）Ａ，ＧｄＡｌＯ３属正交晶系，ａ－５．２５１１（３）Ａ，ｂ－５．３０１７（２）Ａ，ｃ＝７．４４５０（３）Ａ。言语中对钙钛矿结构的ＲＡｌＯ３（Ｒ＝稀土元     

PVC／CEVA共混体系相容性研究

采用ＤＳＣ对ＰＶＣ／ＣＥＶＡ溶液共混物的玻璃化转变进行了研究。结果表明，对ＣＥＶＡ／ＰＶＣ质量比分别为１：９、２：８、４：６、８：２的共混体系，各共混物均分别出现一个明显的玻璃化转变温度，表明ＶＡｃ质量含量为５．９％，但氯含量为５８％的ＣＥＶＡ与ＰＶＣ具有较好的相容性，这是ＣＲ－ＭＭＡ－ＣＥＶＡ接枝共聚物对增塑ＰＶＣ人造革显示出较高粘合性能的主要根源。     

Structural and optical properties of AlxOy/Pt/AlxOy multilayer absorber

We report on the microstructure and optical properties of Al_xO_y–Pt–Al_xO_y interference-type multilayer films, deposited by electron beam (e-beam) deposition onto corning 1737 glass, silicon (1 1 1) and copper substrates. The structural properties were investigated by Rutherford backscattering spectrometry, X-ray diffraction, scanning electron microscopy, energy dispersive X-ray spectroscopy and atomic force microscopy. The optical properties were extracted from specular reflection/transmission, diffuse reflectance and emissometer measurements. The stratification of the coatings consists of a semi-transparent middle Pt layer sandwiched between two layers of Al_xO_y. The top and bottom Al_xO_y layers were non-stoichiometric with no crystalline phases present. The Pt layer is in the fcc crystalline phase with a broad size distribution and spheroidal shape in and between the rims of Al_xO_y. The surface roughness of the stack was found to be comparable to the inter-particle distance. The optical calculations confirm a high solar absorptance of ∼0.94 and a low thermal emittance of ∼0.06 for the multilayer stack, which is attributed not only to the optimized nature of the multilayer interference stacks, but also to the specific surface morphology and texture of the coatings. These optical characteristics validate the spectral selectivity of the Al_xO_y–Pt–Al_xO_y interference-type multilayer stack for use in high temperature solar-thermal applications.     

Optimization of AlxOy/Pt/AlxOy multilayer spectrally selective coatings for solar-thermal applications

Spectrally selective Al_xO_y/Pt/Al_xO_y multilayer absorber coatings were deposited onto corning 1737 glass, Si (111) and copper substrates using electron beam (e-beam) vacuum evaporator at room temperature. The employment of ellipsometric measurements and optical simulation was proposed as an effective method to optimize and deposit multilayer solar absorber coatings. The optical constants (n and k) measured using spectroscopic ellipsometry, showed that both Al_xO_y layers, which used in the coatings, were dielectric in nature and the Pt layer was semi-transparent. The optimized multilayer coatings exhibited high solar absorptance α ∼ 0.94 ± 0.01 and low thermal emittance ? ∼ 0.06 ± 0.01 at 82 °C. The Rutherford backscattering spectroscopy (RBS) data of Al_xO_y/Pt/Al_xO_y multilayer absorber indicated the Al_xO_y layers present in the coating were nearly stoichiometry. The scanning electron microscope analysis (SEM) result indicated that the average diameter and inter-particles distance of Pt grains were statistically about 146 ± 0.17 nm and 6-10 ± 0.2 nm respectively.     

Interfacial microstructure of NiSix/HfO2/SiOx/Si gate stacks

Integration of NiSi_x based fully silicided metal gates with HfO₂ high-k gate dielectrics offers promise for further scaling of complementary metal-oxide- semiconductor devices. A combination of high resolution transmission electron microscopy and small probe electron energy loss spectroscopy (EELS) and energy dispersive X-ray analysis has been applied to study interfacial reactions in the undoped gate stack. NiSi was found to be polycrystalline with the grain size decreasing from top to bottom of NiSi_x film. Ni content varies near the NiSi/HfO_x interface whereby both Ni-rich and monosilicide phases were observed. Spatially non-uniform distribution of oxygen along NiSi_x/HfO₂ interface was observed by dark field Scanning Transmission Electron Microscopy and EELS. Interfacial roughness of NiSi_x/HfO_x was found higher than that of poly-Si/HfO₂, likely due to compositional non-uniformity of NiSi_x. No intermixing between Hf, Ni and Si beyond interfacial roughness was observed.     

Tc trend in high-Tc superconductors

In our previous works, we have shown that most existing ceramic superconductors can be considered to be built of superconductor-semiconductor composite and we have estimated the change in phonon spectrum of the intrinsic superconductor unit if a semiconductor unit is attached to it. Moreover, the proximity effect under the size quantization condition has been examined in the superconductor-semiconductor composite. Each of the stated effects by itself could causeT _c enhancement in general as more semiconductor blocks are added to the system. We extend our study in this paper to analyze the combined actions of phonon spectral change and proximity effect without size quantization condition onT _c variation in members of the Tl₁ series of high-T _c superconductors. Our results indicate that an optimumT _c is obtained if the stated effects are included in the idealized unit cells of the superconductors made up of a superconductor-semiconductor array.     

Anomalous Hall Effect in Sn1?x?yMnxEuyTe and Sn1?x?yMnxEryTe Mixed Crystals

The Anomalous Hall Effect (AHE) was investigated in IV–VI ferromagnetic semimagnetic semiconductors of Sn_1–x Mn _x Te codoped with either Eu or Er. The analysis of experimental data is as follows. Hall resistivity and magnetization showed that AHE coefficient R _s depends on temperature and its value decreases with thetemperature increase. We observe that above ferromagnet–paramagnet transition temperature R _s changes sign. We discuss the possible physical mechanisms responsible for observed temperature dependence of R _s , particularly change of the sign.     

Synthesis of a new perovskite Pb(Li14Nb34)O3

A high-pressure technique was adopted to obtain perovskite-type $\text{Pb(Li}{}_{\mathrm{<mtext>1</mtext><mtext>4</mtext>}}\text{Nb}{}_{\mathrm{<mtext>3</mtext><mtext>4</mtext>}}\text{)}\text{O}{}_3$. A new perovskite $\text{Pb(Li}{}_{\mathrm{<mtext>1</mtext><mtext>4</mtext>}}\text{Nb}{}_{\mathrm{<mtext>3</mtext><mtext>4</mtext>}}\text{)}\text{O}{}_3$ was characterized to have a cubic symmetry with $\text{a}{}_{\mathrm{<mtext>o</mtext>}}\text{= 4.069}\text{A}\text{?}$; Li and Nb ions in the B-site of perovskite lattice may be in a random arrangement.     

Bulk crystalline BaPb34Bi14O3: A ceramic superconductor

The preparation conditions of the high T_C ceramic superconductor Ba(Pb,Bi)O₃ is correlated with the superconducting transition. Transition onsets of all materials are similar, but transition widths and transition completeness is strongly dependent on firing temperature. Only materials prepared over a narrow temperature range, resulting in a nearly ideal weight loss, have a complete and narrow transition.     

Electrostriction in Pb (Zn13Nb23)O3

The electrostriction in $\text{Pb (Zn}{}_{\mathrm{<mtext>1</mtext><mtext>3</mtext>}}\text{Nb}{}_{\mathrm{<mtext>2</mtext><mtext>3</mtext>}}\text{)}\text{O}{}_3$ crystals has been investigated using a strain gauge method. In the ferroelectric phase below 140 C, the strain vs the electric field shows a hysteresis, which is ascribed to the effect of ferroelectric domains. A quadratic relation holds between the strain x and the electric polarization P as x = QP² above about 170 C in the paraelectric phase. Values of the electrostrictive Q coefficients are determined from the measurements near 190 C, as Q₁₁ = 1.6·10^?2m⁴/C², Q₁₂ = ?0.86·10^?2m⁴/C², and Q₄₄ = 0.85·10^?2m⁴/C².     

Magnetic,electrical and thermal studies on the V1−xMox02

The monoclinic-to-tetragonal structure transition of oxides V_1?xMo_x0₂ with $\text{0≤}\text{x}\text{≤0.20}$ has been studied by means of DTA, X-ray diffraction, magnetic susceptibility (powder samples) and electrical conductivity (single crystals) measurements within the temperature region 80 K to 400 K. A linear decrease of the transition temperature of 11 K per atom % Mo was observed. The magnetic susceptibility of the low temperature phase was found to be temperature independent paramagnetic for all preparations. Electrical conductivity measurements on the same phase showed crystals with $\text{x}\text{? 0.04}$ to be semiconducting, while a metallic behavior was observed in the region $\text{0.10 ?}\text{x}\text{? 0.14}$.