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半导体锁模激光器产生的高重复频率的光脉冲序列在众多领域都有着广泛的应用，而对于绝大多数应用，一个固定而准确的重复频率是必须的。由于此种激光器的重复频率主要由激光器波导的有效折射率和腔长来确定，激光器制成以及解理时的不确定性就可能会给其重复频率带来偏差。为了弄清此种激光器的各种工作条件会怎样影响其重复频率从而对上述的偏差进行补偿，设计并制成了一种2 μm GaSb基单量子阱锁模激光器。激光器采用两段式结构（增益区，饱和吸收体区）并可以在高达60 ℃实现稳定的锁模工作模式。系统地记录了此激光器重复频率随偏置条件（增益区电流，饱和吸收体区电压）以及工作温度的变化规律，并且对产生这些变化的原因进行了分析。这些工作能够让人们更加清楚地认识锁模激光器的特性，从而更好地达到各种应用所需要的重复频率。Multi-gigahertz optical pulse trains generated from mode-locked semiconductor lasers are promising for a number of applications in many areas. For most of these applications, a fixed and stable pulse repetition frequency is necessary. Since the repetition frequency of such lasers is primarily determined by the effective refractive index of the laser waveguide and the laser cavity length, uncertainties during device fabrication as well as cleaving process may bring deviations to the repetition frequency. To gain better knowledge of how working conditions of such lasers effect their repetition frequency and thus compensate the above-mentioned deviations, a novel 2 µm InGaSb/AlGaAsSb single quantum well (SQW) mode-locked laser (MLL) was presented in this work. It has a two-section configuration (gain section and saturable absorber section separated by an electrical isolation region) and stable mode locking was achieved in this laser under a variety of bias conditions up to 60 ℃. Repetition frequency variations of this mode-locked laser with bias condition (gain section current I , absorber section voltage V ) and working temperature (T) were systematically recorded, and the mechanisms behind these variations were analyzed. It is believed that this work enables us to have a better understanding of passively mode-locked semiconductor lasers and is of interest to better meet the application-required frequencies. g a National Research Foundation (NRF) Accepted version 新加坡国家研究基金会（NRF-CRP12-2013-04）；中国国家自然科学基金（61964007，61790583）；广东省重点领域研发计划项目（2020B0303020001）

展示了一种低阈值(~131 A/cm2)2 μm InGaSb/AlGaAsSb单量子阱(Single Quantum Well, SQW)激光器, 并对该激光器的理想因子n进行了研究。激光器的总体理想因子n由中央pn结的理想因子n和n型GaSb衬底与n型金属之间形成的整流结的理想因子n两部分组成。当温度从20 ℃升高到80 ℃时, 激光器的总体理想因子n从4.0降低至3.3。该结果与所使用的理论模型以及独立的GaSb材料整流结(pn结、GaSb/金属结等)理想因子n的数值是相吻合的。2 µm InGaSb/AlGaAsSb single quantum well(SQW) laser with low threshold current density of ~131 A/cm and its ideality factor n was presented. The ideality factors n of the central p-n junction and the n-GaSb/metal junction sum up to be the total ideality factor n of the laser. The total ideality factor n decreases from 4.0 to 3.3 when the temperature was increased from 20 to 80℃. The results are in good agreement with the applied theoretical model as well as the ideality factor n of the individual GaSb -based junctions(p-n junction, GaSb/metal junction etc. ). 2 National Research Foundation (NRF) Published version 新加坡国家研究基金会（NRF-CRP12-2013-04）;国家自然科学基金（61790581，61790582，61435012，61308051）

Combined Gauss function with Maximum Average Correlation Height(MACH) algorithm,Gauss-Maximum Average Correlation Height(GMACH) filter is designed.The Hybrid-Distortion target(existing the scale distortion and rotation distortion simultaneously) could be recognized with GMACH filter.In order to improve the Hybrid-Distortion target response ability of the GMACH filter,the standard deviation σ,output noise variance coefficient α,the average correlation energy coefficient β and average similarly measure coefficient γ are optimized and balanced.Through the simulation experiment,it is known that the arbitrary hybrid-distortion target can be recognized by a single GMACH filter within the distortion tolerance range(the scale distortion tolerance is 0.92~1.16 times and the rotation distortion tolerance is-8~24 degrees).As experiment example,a plane under cluttered background was recognized using the GMACH filter.Experiment results prove the feasibility of this method.

To solve the problem of excessive demand for remote network bandwidth when transmit color high-definition image through ethernet,this article gives a compression and transmission solution based on the combination of JPEG2000 Video Codec ADV212 and a FPGA with control logic.This system use a Bayer Pattern CMOS image sensor as data source,use the ADV212 to achieve fast high-quality image compression,the FPGA implements the entire system control logic,such as configuration on the ADV212,pre-distribution image,driving ADV212 under its timing and package the compressed stream.The experiments show that the system can guarantee to receive the image having a high peak signal to noise ratio,long-term stability 36 Mbyte/s image input conditions,and the system is small and easy to use,low bandwidth consumption and the compression ratio is adjustable and so on.

ZnO:Mn thin films were prepared on glass substrates using RF magnetron sputtering method.Raman spectroscopy,X-ray diffraction spectra and SEM were used to analyze the structural characteristics of ZnO:Mn films with the different working pressure.The results show that ZnO:Mn thin films have the significant wurtzite structure with the different working pressure.The leftshifts of the Raman peaks corresponding to E2(High) mode and related to Mn doping are explained by the appearance of much more lattice defects and disorder in ZnO:Mn films with decreasing working pressure,which are also evidenced by XRD and SEM results.

ZnO∶ Mn thin films with different Mn concentration were prepared on glass substrates at room temperature using RF magnetron sputtering method.Raman spectroscopy,X-ray diffraction spectra and SEM were used to analyze the structural characteristics of the ZnO∶ Mn films.The results show that ZnO∶ Mn thin films have significant wurtzite structure with Mn doping mole fraction from 0 up to 5.6%.The redshift of Raman peaks at 437 cm-1and 527 cm-1can be explained by the lattice defects and disorder induced by the increasing of Mn concentration.The appearance of Raman spectra at 647 cm-1indicates the formation of MnO,leading to the worse crystallization of ZnO∶ Mn films,which is also evidenced by XRD and SEM results.

For the peculiar Smear noise occurred in the area CCD imaging,a method to extract the Smear from the interline transfer CCD dark pixel region was proposed by taking an interline transfer area CCD for an example.The working principle of the area CCD was introduced,the creation reason of the Smear was analyzed and the composition of the Smear noise was discussed.Then,the KTC noise and the dark current noise of the Smear were filtered by using the Correction Double Sample(CDS) and the dumb pixel correction.The average filter method based on a middle value was proposed to eliminate the light shot noise.Finally,the Smear was eliminated from a original image by the subtract method,and the Smear image region was compensated by the triangle-based interpolation.A real-time hardware processing system was designed by using Field Programming Gate Array + Digital Signal Processor(FPGA + DSP) as the core processor.When the camera is working at the fastest working mode 3 frame / s,the Smear can be extract and filtered in 1.265 ms and the gradation variance of the image area has decreased to 95.34% by eliminating the Smear.With the imaging experiment verification,the system has a high integration and real-time ability and the Smear noise is eliminated completely.

This paper put forward an available method aimed at the requirements of aerial camera with multi-mode.Driving schedules of interline transfer progressive scan KAI-2093 CCD sensor produced by Kodak corporation have been examined based on the structure and theory of dual-channel transmission.Three kinds of driving mode have been designed: binning,no-binning and TDI mode.The design takes the FPGA EP1C6Q240 produced by Altera corporation as the schedule generator to realize data cache and mosaics.QUARTUSII7.0 has been chosen as the software design platform.Driving schedule generator is described with VHDL.The design of data cache and mosaics has been fulfilled though simulation by Modelsim AE6.1b.Experimental results indicate that the schedule can output CCD signals at the speed of 60 frames/s,120 frames/s etc in binning mode,which can meet the requirements of moving target tracking with high speed;and can output full frame at the speed of 30 frames/s in no-binning mode;and does not affect image quality for long-time working in TDI mode.The system integration and anti-jamming capability have been improved.

In order to solve the vignette phenomenon in the central visual field of the reflecting-mirror-jointed camera,the reasons of the vignette phenomenon were analyzed,and the vignette energy distribution mathematics model was obtained. The vignette energy distribution curve was got using the mathematics model with MATLAB. At the same time,considering the veiling glare of the joint reflecting mirrors and the CCD responding heterogeneity,the radicalization calibration experiment for the CCD camera was carried out. The vignette area was shown by the mathematics model,with function approach law to draft the compensation factor curve of each point in the vignette area,reaching the relation of the compensation factor and the brightness value. Handling the radicalization calibration image and the outfield image,the vignette phenomenon was solved very well.

Using VCCD1024H made in Sarnoff as image sensor,a multi-port area CCD imaging system based on FPGA was designed. VCCD1024H working principle,the whole structure of imaging system,driving circuit,working mode and design of FPGA timing logic were particularly introduced. Then,the imaging timing sequence and the storage of multi-port data were mainly discussed. The logic design of FPGA could meet the demand of imaging and data transmission through simulation and verification. The imaging system will establish reliable foundation for the future application.

Much of the North China Plain( NCP) is dedicated to cultivation of winter wheat and summer maize. In order to achieve high crop yields,nitrogen fertilizer has been used in excess,constituting the major cause of water pollution in the area. The saying that"all rivers are dry and polluted"has come to characterize the NCP's water resource environment. The grey water footprint of a product( WFproc,grey) is a novel method for quantitatively estimating water resource pollution due to agricultural production. Using agricultural data accurate at the county scale,we evaluated the WFproc,greyof crops grown in the NCP from 1986 to 2010 and analyzed spatial and temporal variability. The WFproc,greyof winter wheat was found to be0. 55—2. 97 m3/ kg and that for summer maize was 0. 50—2. 02 m3/ kg; these values are significantly higher( 2—10times) than those for similar crops grown in the rest of the world,such as the U. S. and Germany. On comparing regions within the NCP,we found relatively low WFproc,greyvalues for crops grown in Hengshui,Baoding,and some regions of Hebei province,while it was high for crops grown in Bohai Bay. The total grey water volume of winter wheat and summer maize production over 25 years was estimated in the range of 2. 67 × 1010—5. 84 × 1010m3,with an average of 3. 90 × 1010m3;despite yearly fluctuations,a sustained upward trend was apparent. In light of these results,the need becomes apparent for a reduction in the amount of fertilizer used in agriculture,improvements in the efficiency of applied fertilizer,the development of new methods( such as formula fertilization by soil testing and controlled-release fertilizers),and the replacement of traditional fertilizer with organic fertilizer and biogas slurry. Water resource pollution can be further reduced by preventing fertilizer losses from surface runoff and leaching into groundwater,adopting water-saving irrigation techniques( e. g.,drip irrigation and micro irrigation with integrated water and fertilizer technology),reducing water and soil loss via straw mulching and film mulching,and increasing water storage and organic matter accumulation in subsoil.