基于分离式二极管的220GHz 高效率倍频器

在分离式二极管的基础上,实现了220 GHz高效率的二倍频器结构。该倍频器的电路在450 μm宽,2.7 mm长的50 μm石英基片上实现。测试结果表明,在室温下当驱动功率在46.4~164 mW时,在214~226 GHz的频段内能够实现大于16%的倍频效率。另外,当驱动功率在161 mW时,倍频器在218 GHz频点能够输出最高功率32 mW,并且在多个频点拥有高于20%的倍频效率。实验证明,所实现的二倍频器能够作为660 GHz倍频链路的驱动前级使用。     

基于分离式二极管的220 GHz高效率倍频器（英文）

在分离式二极管的基础上,实现了220 GHz高效率的二倍频器结构.该倍频器的电路在450μm宽,2. 7mm长的50μm石英基片上实现.测试结果表明,在室温下当驱动功率在46. 4～164 mW时,在214～226 GHz的频段内能够实现大于16%的倍频效率.另外,当驱动功率在161 mW时,倍频器在218 GHz频点能够输出最高功率32 mW,并且在多个频点拥有高于20%的倍频效率.实验证明,所实现的二倍频器能够作为660 GHz倍频链路的驱动前级使用.     

0.2 THz二倍频器研究

基于六阳极结反向串联型GaAs平面肖特基二极管,设计并实现了0.2 THz大功率二倍频器。肖特基二极管倒装焊接在50m石英电路上。采用电磁场和电路联合设计仿真获得了二倍频器的倍频效率。当入射功率在100 mW时,输出频率在190~225 GHz带内效率大于5%。在小功率（Pin100 mW）和大功率（Pin300 mW）注入条件下,测试了倍频电路的输出功率和倍频效率。在100 mW驱动功率下采用自偏压测试,最大输出功率为14.5 mW@193 GHz,对应倍频效率为14%;在300 mW驱动功率下采用自偏压测试,在188~195 GHz,输出功率大于10 mW,最大输出功率为35 mW@192.8 GHz,对应倍频效率为11%。     

无基片空间合成的220 GHz三次倍频电路研究

基于四阳极结同向串联型GaAs平面肖特基二极管,设计并实现了无基片空间合成的220 GHz三次倍频电路。采用四支肖特基二极管协同工作,在脊波导小片上下两侧各倒装焊接两支肖特基二极管,构成上下反向结构。采用场路结合的方式,对倍频电路的倍频效率进行了仿真。仿真结果显示输入功率为300 mW,输出频率为213~229 GHz时,倍频效率大于3%;采用E波段功率放大器推动三次倍频电路,获得了倍频器输出功率。测试数据表明,驱动功率为300 mW时,输出频率为213~229 GHz时,输出功率大于5 dBm,倍频效率为1%~2%。     

140 GHz二倍频器的研制

太赫兹通信中本振链输出功率无法满足实际需求,因此提出一种基于肖特基变容二极管的宽带、高效率140 GHz 二倍频器设计方案。该倍频器结构基于波导腔体石英基片微带电路的混合集成方式实现。采用三维有限元与非线性谐波平衡联合仿真方法,实现了倍频器的最优化设计。根据仿真结果,完成了140 GHz二倍频器的加工、制作与测试工作。实测结果表明,在20 dBm的驱动功率下,倍频器的输出功率最高达6.6 mW,倍频效率7.15%;输入功率23 dBm对应的最大输出功率可达11.2 mW。该器件的成功研制使得实现太赫兹通信中的本振链成为可能。     

140GHz二倍频器的研制

太赫兹通信中本振链输出功率无法满足实际需求,因此提出一种基于肖特基变容二极管的宽带、高效率140 GHz二倍频器设计方案。该倍频器结构基于波导腔体石英基片微带电路的混合集成方式实现。采用三维有限元与非线性谐波平衡联合仿真方法,实现了倍频器的最优化设计。根据仿真结果,完成了140 GHz二倍频器的加工、制作与测试工作。实测结果表明,在20 dBm的驱动功率下,倍频器的输出功率最高达6.6 mW,倍频效率7.15%;输入功率23 dBm对应的最大输出功率可达11.2 mW。该器件的成功研制使得实现太赫兹通信中的本振链成为可能。     

大功率单路和功率合成式100～115 GHz肖特基平衡式二倍频器（英文）

研究了基于肖特基二极管的单路和功率合成式110GHz大功率平衡式二倍频器。单路倍频器电路具有33%的峰值测试效率,且其工作带宽超过13.6%。另外,采用了不同的双路合成结构来实现两种不同的合成式110 GHz倍频器。该功率合成式倍频器在两只127 μm厚的ALN基片上焊接了四个分立的肖特基二极管。在800 mW的驱动功率下,两种合成式倍频器都测得了大于200 mW的输出功率,证明了利用该合成式倍频结构可实现更高输出功率。     

大功率单路和功率合成式100~115GHz 肖特基平衡式二倍频器

研究了基于肖特基二极管的单路和功率合成式110 GHz大功率平衡式二倍频器。单路倍频器电路具有33%的峰值测试效率,且其工作带宽超过13.6%。另外,采用了不同的双路合成结构来实现两种不同的合成式110 GHz倍频器。该功率合成式倍频器在两只127 μm 厚的 ALN 基片上焊接了四个分立的肖特基二极管。在800 mW的驱动功率下,两种合成式倍频器都测得了大于200 mW的输出功率,证明了利用该合成式倍频结构可实现更高输出功率。     

基于片上肖特基二极管的高功率三倍频器设计

提出了一种基于片上集成电容工艺和带阻滤波结构的高功率三倍频器设计方法。在倍频器输入端,首先对倍频器二极管的直流偏置馈电部分进行改进,在梁式引线结构基础上结合二氧化硅（S_iO₂）工艺实现了片上集成电容,同时解决了三倍频器的直流馈电和射频接地问题,实现电路功能集成的同时也提高了模型仿真精度。此外,在二极管的输入端采用带阻滤波器结构替代传统的低通滤波结构,在保证倍频器性能的同时进一步简化倍频器结构复杂度和尺寸。为进行验证,设计并加工测试了两款中心频率分别为110 GHz和220 GHz的双路功率合成三倍频器。实际测试结果表明,在输入功率500 mW条件下,110 GHz三倍频器的输出峰值功率达到了140 mW,峰值效率接近30%,带宽超过15 GHz;在输入功率300 mW条件下,220 GHz三倍频器的输出峰值功率达到了45 mW,峰值效率达到15%,带宽为15 GHz。两款倍频的测试结果均有优秀表现,验证了设计方法的有效性。     

高功率110 GHz平衡式肖特基二极管频率倍频器

高频段的太赫兹信号通常是由多个倍频器级联输出的,因此要求倍频链路的前级必须具备高输出功率的能力。为了提升太赫兹倍频器的功率容量和效率,结合高频特性下肖特基二极管有源区电气模型建模方法,采用高热导率的陶瓷基片,利用对称边界条件,在HFSS和ADS中实现对倍频器电路的分析和优化,研制出了高功率110 GHz平衡式倍频器。最终测试结果表明,驱动功率为28 dBm左右时,该倍频器在102~114.2 GHz的工作带宽内的最高输出功率和效率分别为108 mW和17.6%,为链路后续的二倍频和三倍频提供足够的驱动功率。     

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.     

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.     

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.     

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.     

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.     

中国建立EB级存储实验室,致力云计算应用(英文)

正With the support of 863 programs,Sugon Information Industry Co.,Ltd.,set up a dawning EB-class storage laboratory to address massive data storage requirements and largescale cloud computing demonstration applications.The Dawning EB-class cloud storage system adopts advanced fault-tolerant architecture,efficient data fault-tolerant algorithms with user authentication and data encryption policies to deal with the"lost""wrong"and"stolen"problems of data for ensuring the reliability and safety of the EB-class storage system in the public network application environments.The Dawning EB-class Storage Laboratory taking advan-