集成光学迈克尔逊干涉型加速度地震检波器

为了提高地震检波器的检测灵敏度,增强其性能可靠性,使其体积微型化,利用集成光学原理设计研制了迈克尔逊干涉芯片,并与光纤-质量块简谐振子、光源、光电探测器制成迈克尔逊干涉型加速度地震检波器,检波器具有灵敏度高、频带宽、重量轻、抗电磁干扰等优点,设计参数相位检测灵敏度Δ/a 为1 1×10-2 rad/(m s-2),测试结果表明,在工作频带0~1065 Hz内,振动与检波器输出信号吻合良好,达到设计要求.     

K波段低相位噪声频率综合器的设计与实现

采用双锁相环混频设计方案,设计了一种低相位噪声频率综合器,实现了单锁相环难以实现的低相位噪声指标。在系统理论分析的基础上,优化了电路布局,实际的电路尺寸为45.0 mm×30.0 mm×12.0 mm,实现了小型化K波段低相位噪声频率综合器。对频率综合器电路进行了测试,输出信号相位噪声为 -95 dBc/Hz @1 kHz和 -99 dBc/Hz @≥40 kHz,杂散为-72 dBc,完全满足设计指标的要求。     

多相位低相位噪声5GHz压控振荡器的设计

采用TSMC 0.18μmCMOS工艺实现了全差分相位差为 450 的 LC低相位噪声环形压控振荡器电路。芯片面积 1.05 mm×1.00 mm。当仅对差分输出振荡信号的一端进行测试时, 自由振荡频率为5.81 GHz, 在5 MHz频偏处的相位噪声为-101.62 dBc/Hz。     

M-Z干涉型集成光学微加速度传感器结构设计

提出了一种新型的Si基M Z干涉型微光电机械系统(MOEMS)加速度地震检波器。在Si基上集成了Si十字梁、质量块、偏振器、M Z波导干涉仪及声光调制器。给出了该加速度检波器工作原理,对结构进行了分析设计,并用有限元(FEM)分析软件进行了仿真计算。该检波器的主要设计参数为:固有频率1353Hz,相位检测灵敏度1.2×10-4rad/(m·s2)。     

一种用于UHF波段收发系统的CMOS小数N分频频率综合器

本文设计并实现了一种应用于超高频射频识别（Ultra High Frequency Radio Frequency , UHF）阅读器的ΔΣFractional-N频率综合器。采用4bit的开关电容阵列实现了885MHz~1020M的16 (2^4)个子带的VCO;7/8双模预分频器使用源极电流耦合逻辑（Source Current Mode Logic, SCML）结构的D触发器及脉冲吞吐电路实现;使用四位三阶的Single-loop 结构实现ΔΣ调制器。频率综合器的频率分辨率为200Hz;参考频率为12.95MHz,仿真结果表明当环路带宽为2π×50k时频率锁定时间小于100us。电路采用UMC 0.18μm 2P6M CMOS工艺制备,芯片面积为1.4mm×1.5mm,测试结果表明电源电压1.8V时功耗20mA,测试总输出相位噪声为：-120.6dBc/Hz @1MHz 和 -95.0dBc/Hz @100kHz。     

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。     

一种应用于多频接收机的宽带频率综合器

采用0.18µm 1P6M CMOS工艺实现了一种应用于多频接收机的整数分频频率综合器。该频率综合器为接收机提供频率分别为2.57GHz, 2.52GHz, 2.4GHz 和 2.25GHz的本振信号。为了覆盖要求的频点,其宽带压控振荡器同时采用了可变电容阵列和可变电感阵列。经测试,压控振荡器的频率调谐范围为1.76GHz~2.59GHz。对于频率为2.57GHz, 2.52GHz, 2.4GHz 和 2.25GHz的载波,在1MHz频偏处,相位噪声分别为-122.13dBc/Hz、-122.19dBc/Hz、-121.8dBc/Hz和-121.05dBc/Hz。其带内相位噪声分别为-80.09dBc/Hz、-80.29dBc/Hz、-83.05dBc/Hz 和-86.38dBc/Hz。包括驱动电路在内的芯片功耗约为70mW。芯片面积为1.5mm×1mm。     

宽带低相噪CMOS LC VCO的设计

设计了一款宽带CMOSLCVCO,在分析VCO相位噪声来源的基础上,对VCO进行了结构优化和噪声滤除,并采用了开关电容阵列以增加带宽。电路采用0.18μmCMOS射频工艺进行流片验证,芯片面积为0.4mm×1mm。测试结果显示:芯片的工作频率为3.34～4.17GHz,中心频率为4.02GHz时输出功率是-9.11dBm,相位噪声为-120dBc/Hz@1MHz,在1.8V工作电压下的功耗为10mW。     

空心顺变柱体型三分量全光纤加速度地震检波器

设计了介绍一种新型空心顺变柱体型三分量全光纤加速度地震检波器。该检波器作为加速度检测设备,采用3个迈克尔逊光纤干涉仪光路,用6个空心顺变柱体共同支撑1个质量块构成三维简谐振子系统。对实验样机进行的模拟实验测试表明:共振频率为308Hz,工作频带向低频移动,频响特性曲线与理论计算相符。加速度灵敏度的理论计算值为15.7×103rad/g,能满足大多数场合下对加速度精确测量的要求。     

1阶反馈稳定光纤3×3耦合器干涉测量系统

为了消除环境干扰对光纤干涉测量系统的影响,采用光纤3×3耦合器和光纤光栅构成光路复合在一起的两个光纤迈克尔逊干涉仪构成了光纤干涉测量系统。利用光纤光栅作为反射镜,两个光纤迈克尔逊干涉仪共有几乎相同的光路。其中一个光纤迈克尔逊干涉仪通过一个1阶反馈来补偿环境干扰的影响,实现对该测量系统的稳定;另一个光纤迈克尔逊干涉仪用于完成测量工作。结果表明,1阶反馈可以对0Hz～21Hz的干扰进行补偿,使得该测量系统适合于在线精密测量。     

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.     

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.     

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.     

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.     

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     

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