大功率高效率2μm锑化镓基量子阱激光器（英文）

通过MBE外延系统生长了2μmGaSb基AlGaAsSb/InGaSbI型量子阱激光器,并制备了宽面条形波导激光器件,在20℃工作温度下,器件最大连续激射功率达到1.058W,当注入电流为0.5A时,峰值波长为1.977μm,最大能量转换效率为20.2%,在脉冲频率为1000Hz,占空比为5%的脉冲工作模式下,最大激射功率为2.278W.     

2微米AlGaAsSb/InGaSb I类量子阱大功率激光器

通过分子束外延的方式生长了2微AlGaAsSb/InGaSb I类量子阱大功率激光器。制备了脊条形波导的激光二极管以及激光器线列（4个发射单元）,腔面均未镀膜。对单个激光二极管,在10℃工作温度下,最大连续激射功率为0.5W,阈值电流密度为150A/cm2,斜率效率为0.17W/A,在脉冲宽度为100微秒,5%占空比的条件下,其脉冲光功率达到0.98W。对激光器线列,室温最大连续激射功率为1.02W,最大脉冲激射功率达到3.03W。     

大功率及高转换效率2.1μm GaInSb/AlGaAsSb量子阱激光器

报道了激射波长为2.1 m 的GaInSb/AlGaAsSb双量子阱激光器。通过优化外延结构设计和欧姆接触,无镀膜的宽条激光器达到了9.8%的峰值功率转换效率,这比原来的值提高了1.5倍,室温下得到了615 mW的连续激射功率输出和1.5 W的脉冲激射功率输出。这些激光器的阈值电流密度低至126 A/cm2,斜率效率高达0.3 W/A。通过测试不同腔长的激光器,测得内损耗和内量子效率分别为6 cm-1和75.5%,均比原有器件有很大提升。激光器在连续工作3 000 h后,功率没有明显下降。     

高功率窄脉冲垂直腔面发射激光器n-DBR反射率的优化

从理论上研究了n型分布布拉格反射镜(n-DBR)的反射率对器件阈值电流、输出功率以及转换效率的影响,得出了最佳反射率。在此基础上研制了垂直腔面反射激光器(VCSEL)单管和阵列器件,采用波形分析法对VCSEL器件的功率进行了测试。在脉冲宽度60ns,重复频率100Hz条件下,500μm口径单管器件在注入电流为110A时,峰值输出功率达102W,功率密度为52kW/cm2,4×4、5×5阵列器件在100A时,功率分别达到98W和103W。对比了单管器件在连续、准连续和脉冲工作条件下的输出特性和光谱特性,连续和准连续条件下激射波长的红移速率分别为0.92nm/A和0.3nm/A,6A时的内部温升分别为85℃和18℃,而脉冲条件下激射波长的红移速率仅为0.0167nm/A,6A时的温升为1.5℃,远小于连续和准连续的情况,这也是器件在脉冲条件下能得到很高输出功率的主要原因。     

940 nm 20%占空比InGaAs/AlGaAs大功率LD线阵

采用金属有机化合物气相淀积(MOCVD)技术,制作了AlGaAs/InGaAs/GaAs大功率20%占空比半导体激光器.采用良好的封装方式,激光器直接封装在高效导热载体上,对载体水冷散热,在脉冲频率500 Hz,脉冲宽度400 μs下,驱动电流105 A时输出功率高达90.6 W,最高电-光转换效率42.3%,斜率效率0.94 W/A.器件中心激射波长941.8 nm,光谱半高全宽3.3 nm.     

垂直外腔面发射半导体激光器的双波长调控研究

报道了一种结构紧凑的垂直外腔面发射激光器（Vertical-External-Cavity Surface-Emitting Laser,VECSEL）及其双波长调控。通过调控泵浦光功率,实现了VECSEL输出的两个激光波长之间的相互转换,双波长的间隔接近50 nm。VECSEL的输出功率曲线呈现明显的两次翻转,翻转点对应了激射波长的转换。这是由于泵浦功率变化改变了增益芯片内部的温度,进而通过热调谐使得发光区增益峰值被调谐到腔模的不同位置。在0℃时,每个激射波长的最大输出功率都在1.5 W以上。随着泵浦功率的改变,激射波长可以在950 nm和1000 nm之间切换,同时还可以在1.5 W以上的功率水平下实现双波长同时激射。这种可切换波长及双波长同时激射的VECSEL器件在光调制、差频等领域有较大应用潜力。     

980nm大功率垂直腔底发射激光器

报道980nm大功率底发射垂直腔面发射激光器的结构、研制及器件的阈值电流、输出功率和光谱特性．在室温(24℃)下，5A连续电流工作时，出光孔径400μm的器件激射波长为984．1nm，输出功率达到1．42W，是目前所能见到报道中最高的．研究了出光孔径600μm的器件在连续工作时，激射波长、光谱半高宽随注入电流的变化以及在重复频率100Hz，脉冲宽度50—1000μs条件下的输出功率、效率与注入电流的关系．     

1.46～1.66GHz 250W宽带硅微波脉冲大功率管

报道了L波段高端中脉冲250W宽带硅微波脉冲大功率晶体管研制结果.该器件采用微波功率管环台面集电极结终端结构、非线性镇流电阻等新工艺技术,器件在1.46～1.66GHz频带内,脉宽200μs,占空比10%和40V工作电压下,全带内脉冲输出功率大于250W,功率增益大于7.0dB,效率大于45%.     

1.46~1.66GHz 250W宽带硅微波脉冲大功率管

报道了L波段高端中脉冲250W宽带硅微波脉冲大功率晶体管研制结果.该器件采用微波功率管环台面集电极结终端结构、非线性镇流电阻等新工艺技术,器件在1.46～1.66GHz频带内,脉宽200μs,占空比10%和40V工作电压下,全带内脉冲输出功率大于250W,功率增益大于7.0dB,效率大于45%.     

4H-SiC MESFET工艺中的高温氧化及介质淀积技术

采用自主开发的4H-SiC高温氧化技术,并结合低压化学气相淀积方法,在器件表面形成较为致密的氧化层,降低了器件的反向泄漏电流,提高了器件的击穿电压,同时也提高了器件的输出功率及功率增益,为器件长期稳定可靠工作奠定了工艺基础。采用此技术后,单胞20 mm左右栅宽器件在2 GHz脉冲条件下(脉冲宽度300μs,占空比10%)输出功率达78 W,比原工艺的器件输出功率提高了20 W以上,功率增益提高了1.5 dB,达到8.9 dB左右,功率附加效率也从23%提升到32%,初步显示了该工艺技术在制备4H-SiC微波功率器件中的优势。     

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-