基于时分外差法检测的非对称薄壁壳型光纤一维地震波检波器

研制了基于时分外差法检测的非对称薄壁壳型光纤一维地震波检波器, 该检波器易于扩展为三轴分立式地震波检波器, 具有检测动态范围大, 易于构成大规模时分复用传感网络的优点。建立了非对称地震波检波器的理论模型, 分析了各结构参数对其灵敏度的影响; 搭建了基于光学同步参考信号的时分外差法测试系统, 进行了外差系统的稳定性测试, 测量了地震波检波器的频响曲线, 结果表明外差系统测量信号波动小于0.1dB; 工作频段20~800Hz内加速度平均灵敏度为28.5dB re rad/g, 与理论仿真结果基本吻合。     

基于红宝石探头的荧光光纤温度传感器的研究

基于荧光强度的温度测量原理,设计了一种利用荧光波分和时分多路传输技术,通过检测红宝石晶体的荧光强度实现温度测量系统。通过对探头的合理设计减少了激励光的泄漏,提高了系统的信噪比和灵敏度,电子信号处理采用2个绿色LED和1个红色LED驱动电路将荧光信号和参考信号分离,提高了系统的稳定性。实验表明,该系统可实现温度的高精度测量,测量温度范围300~430 K,分辨率为±0.5℃,探头误差为±3 K,信噪比为35 dB。     

基于FPGA的插频式外差干涉信号处理方法

为了测得外差干涉仪的相位移,采用插频法对外差干涉仪的参考信号与测量信号进行了处理,从而测得两个信号的相位差即多普勒频移.插频法基于过零检测原理,即在测量信号与参考信号上升沿来临时,分别对两信号插入脉冲,通过对插入的脉冲计数,实现相位差的测量.外差干涉仪光源是拍频为2.2MHz的He-Ne激光,使用迈克尔逊干涉仪测量系统...     

用脉冲计数技术提高接收机的灵敏度

本方法可以检测到低于 HP8551B 频谱分析仪噪声基底35dB 的弱微波信号。外差接收机通常不能检测功率电平低于系统灵敏度的输入信号。使用带有电子计数器的外差接收机可以提取比基底噪声低得多的这类弱信号。     

基于3×3相位解调的光纤地震检波器研究

针对基于3×3相位解调的光纤地震检波器展开研究.利用基于最小二乘法的椭圆拟合法和微分交叉相乘算法,实现基于3×3相位解调的光纤地震检波器的两路输出信号的归一化,减小光纤3×3耦合器的非对称性和激光器的功率波动对光纤地震检波器的影响,解调出光纤地震检波器的相位,实现振动信号的准确还原.实验采用对比法测试了基于3×3相位解调的光纤地震检波器的性能,其灵敏度为320 rad/g@100 Hz,在5～400 Hz频率范围内的波动约为0.7 dB.该研究能够很好地应用于石油、天然气等地质勘探、地震监测以及周界安防等领域.     

基于Filterlab的一种高指标带通滤波器的设计

为了提取激光外差玻璃测厚系统中的微弱信号,介绍了激光外差玻璃厚度测量系统原理及待检测信号特征,采用一种简洁、实用的滤波软件,设计出一种高指标带通滤波器,从滤波器频谱图看待检测的激光外差信号频谱完全在通频带内,噪声衰减带达到80 dB,其完全符合系统要求。     

基于双金属膜片结构的海底地震勘探光纤加速度传感器研究

针对全光海底地震检波器技术的特殊应用需求,设计了一种基于双金属矩形膜片的缠绕式光纤加速度传感器。利用弹性力学理论对光纤加速度传感器的加速度灵敏度和一阶共振频率的特性进行了分析,制作了光纤加速度传感器样品并对其性能进行了测试。结果表明,本文加速度传感器的灵敏度为45dB re∶0dB=1rad/g,一阶共振频率在820Hz左右,与理论分析值很好吻合。在10～400Hz工作带宽中,交叉去敏度约为30dB。测试系统中,使用的相位生成载波(PGC)解调算法的最小相位检测精度为10-5 rad/Hz1/2,因此理论能探测的最小加速度信号为56ng/Hz1/2。由于采用全金属结构,本文类型光纤加速度传感器能够更好地满足海底永久布放检波器的特殊要求。     

三分量光纤激光检波器阵列及其实验研究

采用波分/空分混 合复用的方案,构建了基于分布反馈光纤激光器(DFBFL)的两级三分量地震检波器阵列, 通过相干探测技 术实现高分辨率的波长解调,并对检波器进行了测试。结果表明,阵列中传感器的本底噪 声小于70ng/√Hz, 对微弱振动信号的探测能力优于传统动圈检波器,三分量检波器的交叉灵敏度小于－20dB,通道间串扰小于－80dB,为多维多分量地震 勘探提供了一种新的技术途径。     

用于水下声光通信的外差式激光多普勒振动计

基于外差激光多普勒原理,设计并实现了一套光纤结构的外差式激光多普勒振动计(LDV).在消声水池,对该系统的探测灵敏度、上行声光通信速率以及水面波浪的影响进行了测试实验.实验结果表明,系统最小探测声压达105.6 dBμPa;在平静水面,无误码情况下,声光通信速率可达5 kbits;在有小波浪的水面,导致部分探测信号丢失,采用扩频调制通信方式,无误码情况下,声光通信速率可达30 bit/s.     

激光多普勒效应在地震波勘探中的应用研究

传统地震检波器为“永磁-动圈”式电磁检波器,在信号捡取过程中易受电磁干扰,存在非线性;基带传输的低频模拟信号(10～300 Hz)会受干扰。提出一种应用切向激光多普勒技术的地震波检测方法,采用优化设计的差动光路结构方案,研究了信号处理单元的适宜带宽。通过F/V转换可以实时地得到被测速度、位移、加速度和频率。实现了线性测量的频率范围1.0～1000Hz,动态范围100dB。     

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.     

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.     

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.     

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.     

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.     

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.     

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.