长周期光纤光栅电压传感器系统

设计了一种基于长周期光纤光栅的电压传感系统.传感长周期光纤光栅横向粘贴在压电陶瓷上,并将被测工频电压施加于压电陶瓷的两端,压电陶瓷在电压的作用下产生同频伸缩并实现对光信号的调制.通过测量长周期光纤光栅的谐振波长的偏移量来获得被测的电压.实验结果表明,该电压传感系统可靠性好,精度高.     

基于微分环干涉技术的光纤长度测量系统

设计了一种利用全光纤干涉系统来精确测量光纤长度的方法。该系统主要由3×3光纤耦合器构成的双光纤微分环和起到相位调制作用的压电陶瓷组成,在微分干涉原理的基础上,对各自通过参照光纤和待测光纤形成的干涉光信号进行相位解调,从而求得待测光纤的长度。实验结果表明测量的光纤长度和已知值一致。     

新型光纤信号调制器

在对光纤回波损耗研究的基础上，设计了一种基于多光束干涉效应的新型光纤信号调制器。实验中，利用两光纤端面间的多光束干涉作用，通过压电陶瓷控制两光纤端面的振荡距离，从而在输出端得到被调制过的光信号。这种光纤信号调制器主要针对信号振幅调制，调制比约为10％，信噪比约为60dB，带宽约为200kHz。该调制器展现了一种新颖的设计思路，可应用于光纤传输信号的调幅及光纤光源交流和脉冲信号的输出等。     

声光调制用压电陶瓷宽频高压驱动电路设计

为了将压电陶瓷应用于声光调制光纤光栅器件,提出了一种宽频带的高压压电陶瓷功放电路。电路采用基于双MOS管BLF175的推挽电路,工作在甲乙类工作状态,实现1¹0MHz正弦信号的高压功率放大。该文对电路设计方法进行了详细分析,介绍了各模块的作用,并说明了电路的具体调试方法。实验结果表明该电路满足宽带高压功率放大要求。     

耦合型光纤超声传感器实验研究

提出了一种用于超声信号测量的耦合型光纤超声传感器并讨论了其工作原理.采用耦合型光纤超声传感器、光电转换控制电路和高分辨率的信号处理软件组建了超声信号检测系统.通过对150 kHz的连续超声信号、脉冲超声信号的测量试验,对耦合型光纤超声传感器的性能进行了检验,实验结果与压电超声传感器的测量结果相吻合,同时研究了光纤超声传感器对不同方向信号的响应特性.实验证明,耦合型光纤超声传感器适用于超声信号的测量.     

光纤干涉仪动态相移测量的新方法及应用

提出了一种光纤干涉仪动态相移测量的新方法.该方法无需对光源进行调制,直接利用干涉信号的直流量和一次谐波分量,通过构造匹配函数的方法求解动态相移,实现了无源零差检测,而且具有信号解调简单、工作频带宽等特点.为了验证该方法的有效性,搭建了一个全保偏Mach-Zehnder光纤干涉仪系统,对压电陶瓷(PZT)产生的模拟动态相移进行求解.结果表明,求解得到的动态相移幅度与加载在PZT上的电压具有很好的线性关系,这与PZT的低频小信号特性一致.最后将该方法用于干涉型光纤水听器声压相位灵敏度频响的测量,实验结果与采用相位载波调制解调方法获得的结果基本吻合.     

声光调制用于全光纤激光器的光谱调谐

描述了采用压电换能器对谐振腔内增益光纤的声光调制,通过控制压电换能器的信号,实现了全光纤激光器的光谱调谐。同时,利用实验制作的可调谐激光器产生了连续可调微波信号,其频率范围1⁴.9GHz。     

剪切模式压电光纤调制器

设计了一种基于剪切模式振荡的光纤光调制器.实验中,利用压电陶瓷控制2段对接光纤的相对截面积,在初始位置光束无损耗的全部通过,在压电陶瓷管切向形变为光纤内径r时,输出光强为零.本光纤信号调制器属于光的振幅调制器,调制度可达到100%,信噪比(SNR)约为25 dB,带宽约为200 kHz.     

磁致伸缩材料被覆保偏光纤磁场传感研究

通过直流磁控溅射镀膜,将磁致伸缩材料———铽镝铁被覆在一段去掉保护层的保偏光纤上,得到铽镝铁被覆保偏光纤结构的磁传感单元。采用保偏光纤及保偏光纤器件,建立马赫-曾德尔光纤干涉仪,将铽镝铁被覆保偏光纤结构的磁传感部分接在干涉仪的一臂中间,另一臂中接入保偏光纤绕制的压电陶瓷调制器进行光纤干涉系统的相位控制。该系统通过压电陶瓷调制器将相位控制在正交工作点上,解决了系统的相位衰落;全保偏光纤结构有效控制了系统偏振诱导的信号衰落,实现了系统对信号的稳定检测。实验得到了系统在不同大小直流偏置磁场作用下的磁场响应特性,结果表明,较大直流偏置磁场可使系统响应灵敏度提高约20倍,最小可测的交流磁场信号达到2.2×10-8T。     

光纤光栅非平衡M-Z干涉解调技术研究

介绍了一种基于直流相位跟踪零差法的非平衡Mach-Zender干涉解调系统的工作原理,设计了一套光纤光栅解调系统,并通过实验分析了该系统的应变精度为8.17×10-3με;对压电陶瓷产生的振动信号进行检测,取得了很好的实验效果。实验结果证明,它有良好的动态性能,适合于精密测试中动态信号的检测。还讨论了影响解调精度的主要因素。     

Preparation and Characterization of TaN ALD Precursors

High purity organic-tantalum precursors for thin film ALD TaN were synthesized and characterized.Vapor pressure and thermal stability of these precursors were studied.From the vapor pressure analysis,it was found that TBTEMT has a higher vapor pressure than any other published liquid TaN precursor,including TBTDET,TAITMATA,and IPTDET.Thermal stability of the alkyl groups on the precursors was investigated using a 1H NMR technique.The results indicated that the tertbutylimino group is the most stable group on TBTDET and TBTEMT as compared to the dialkylamido groups.Thermal stability of TaN precursors decreased in the following order:TBTDET ＞ PDMAT ＞ TBTEMT.In conclusion,precursor vapor pressure and thermal stability were tuned by making slight variations in the ligand sphere around the metal center.     

Curved crystal spectrometer for the measurement of X-ray lines from laser-produced plasmas

In order to diagnose the laser-produced plasmas, a focusing curved crystal spectrometer has been developed for measuring the X-ray lines radiated from a laser-produced plasmas. The design is based on the fact that the ray emitted from a source located at one focus of an ellipse will converge on the other focus by the reflection of the elliptical surface. The focal length and the eccentricity of the ellipse are 1350 mm and 0.9586, respectively. The spectrometer can be used to measure the X- ray lines in the wavelength range of 0.2-0.37 nm, and a LiF crystal （200） （2d = 0.4027 nm） is used as dispersive element covering Bragg angle from 30° to 67.5°. The spectrometer was tested on Shengnang- Ⅱ which can deliver laser energy of 60-80 J/pulse and the laser wavelength is 0.35 μm. Photographs of spectra including the 1 s2p ^1P1-1s^2 ^1S0 resonance line（w）, the 1s2p ^3P2-1s^2 1S0 magnetic quadrupole line（x）, the 1s2p ^3P1-1 s^2 ^1S0 intercombination lines（y）, the 1 s2p ^3S~1-1 s^2 ^1S0 forbidden line（z） in helium-like Ti Ⅹ Ⅺ and the 1 s2s2p ^2P3/2-1 s622s ^2S1/2 line（q） in lithium-like Ti Ⅹ Ⅹhave been recorded with a X-ray CCD camera. The experimental result shows that the wavelength resolution（λ/△ 2） is above 1000 and the elliptical crystal spectrometer is suitable for X-ray spectroscopy.     

Electronic Structure of Semiconductor Nanocrystals

This paper reviews our recent development of the use of the large-scale pseudopotential method to calculate the electronic structure of semiconductor nanocrystals, such as quantum dots and wires, which often contain tens of thousands of atoms. The calculated size-dependent exciton energies and absorption spectra of quantum dots and wires are in good agreement with experiments. We show that the electronic structure of a nanocrystal can be tuned not only by its size,but also by its shape. Finally,we show that defect properties in quantum dots can be significantly different from those in bulk semiconductors.     

Critical Stage Rule-Based Real Time Dispatch（RTD）System in Highly-Mixed-Products （HMP） FAB

An improving utilization and efficiency of critical equipments in semiconductor wafer fabrication facilities are concerned. Semiconductor manufacturing FAB is one of the most complicated and cost sensitive environments. A good dispatching tool will make big difference in equipment utilization and FAB output as a whole. The equipment in this paper is In-Line DUV Scanner. There are many factors impacting utilization and output on this equipment group. In HMP environment one of the issues is changing of reticule in this area and idle counts due to load unbalance between equipments. Here we'll introduce a rule-based RTD system which aiming at decreasing the number of recipe change and idle counts among a group of scanner equipment in a high-mixed-products FAB.     

GaAsSb/InAlAs PA DHBTs Grown by Production MBE

The epi material growth of GaAsSb based DHBTs with InAlAs emitters are investigated using a 4 × 100mm multi-wafer production Riber 49 MBE reactor fully equipped with real-time in-situ sensors including an absorption band edge spectroscope and an optical-based flux monitor. The state-of-the-art hole mobilities are obtained from 100nm thick carbon-doped GaAsSb. A Sb composition variation of less than ± 0.1 atomic percent across a 4 × 100mm platen configuration has been achieved. The large area InAlAs/GaAsSb/InP DHBT device demonstrates excellent DC characteristics,such as BVCEO＞6V and a DC current gain of 45 at 1kA/cm2 for an emitter size of 50μm × 50μm. The devices have a 40nm thick GaAsSb base with p-doping of 4. 5 × 1019cm-3 . Devices with an emitter size of 4μm × 30μm have a current gain variation less than 2% across the fully processed 100mm wafer. ft and fmax are over 50GHz,with a power efficiency of 50% ,which are comparable to standard power GaAs HBT results. These results demonstrate the potential application of GaAsSb/InP DHBT for power amplifiers and the feasibility of multi-wafer MBE for mass production of GaAsSb-based HBTs.     

Noise character analysis and the restraint of self-pulsation laser diodes

We calculate the Langevin noise sources of self-pulsation laser diodes, analyze the effects of active region noise and saturable-absorption region noise on the power fluctuation as well as period fluctuation, and propose a novel method to restrain the noise effects. A visible SIMULINK model is established to simulate the system, The results indicate that the effects of noise in absorption region can be ignored; that with the increase of DC injecting current, the noise effects enhance power jitter, and nevertheless, the period jitter is decreased; and that with external sinusoidal current modulating the self-pulsation laser diode, the noise-induced power jitter and period jitter can be suppressed greatly. This work is valuable for clock recovery in all-optical network.     

High-quality single-crystal CdSe nanoribbons and their optical properties

Large-scale synthesis of single-crystal CdSe nanoribbons is achieved by a modified thermal evaporation method, in which two-step-thermal-evaporation is used to control CdSe sources＇ evaporation. The synthesized CdSe nanoribbons are usually several micrometers in width, 50 nm in thickness, and tens to several hundred micrometers in length. Studies have shown that high-quality CdSe nanoribbons with regular shapes can be obtained by this method. Room-temperature photolumines-cence indicates that the lasing emission at 710 nm has been observed under optical pumping （266 nm） at power densities of 25-153 kW/cm^2. The full width half maximum （FWHM） of the lasing mode is 0.67 nm     

Propagation of hermite-cosh-gaussian beams passing through ABCD optical system with an annular aperture

By using the expansion of the aperture function into a finte sum of complex Gaussian functions, the corresponding analytical expressions of Hermite-cosh-Gaussian beams passing through annular apertured paraxially and symmetrically optical systems written in terms of ABCD matrix were derived, and they could reduce to the cases with squared aperture. In a similar way, the corresponding analytical expressions of cosh-Gaussian beams through annular apertured ABCD matrix were also given. The method could save more calculation time than that by using the diffraction integral formula directly.     

Influence of polarization extinction ratio on distributed polarization coupling detection

Distributed polarization coupling in polarization-maintaining fibers can be detected by using a white light Michelson interferometer. This technique usually requires that only one polarization mode is excited. However, in practical measurement, the injection polarization direction could not be exactly aligned to one of the principal axes of the PMF, so the influence of the polarization extinction ratio should be considered. Based on the polarization coupling theory, the influence of the incident polarization extinction on the measurement result is evaluated and analyzed, and a method for distributed polarization coupling detection is developed when both two orthogonal eigenmodes are excited.     

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正Communications—VLSI Researches and industries of telecommunications have been growing rapidly in the last 20 years and will keep their high growing pace in the next decade.The involved researches and developments cover mobile communications,highway and last-mile broadband communication,domain specific communications,and emerging D2D M2M communications.Radio communication steps into its