高精度激光温控系统设计

针对大功率半导体激光器精确温控较为困难的问题,提出了一种高精度温控系统的设计方法。该系统采用数字PID控制以及细分温度区间的方法,实现了精确温控。在对某大功率激光器的试验中,在高低温环境下,温控精度可以达到±2℃。试验结果表明,该系统温控精度高,加热/制冷效率高,为大功率半导体激光器的温度控制提供了一种良好的解决方案。     

液相外延温控系统与真空系统的全新设计

对液相外延温控系统和真空系统进行了全新的设计,温控系统运用单相可控硅过零触发技术,解决了移相触发技术中使系统电压畸变,功率因数下降的问题.并配以日本神港程序控制器,使得温度精度达到±0.1 ℃,且重复性和稳定性也相应地得到提高.真空系统加入了冲洗气体保护装置,有效地解决了以往冷阱变暖使油蒸汽反流的问题.     

光纤陀螺光源数字温度控制技术

分析了光纤陀螺SLD光源的温度特性 ,设计了SLD数字非线性温度控制方法 ,在宽温度范围内实现了SLD温度的稳定控制 ,并且能实现迅速启动 ,温度过冲控制在± 1K的范围。实验测得温控稳定性达到 0 .0 5K ,启动时间短于 1 2s。通过控制参数的设定 ,此系统可适用于不同的半导体激光器的控温系统     

干燥炉中热风循环温控系统的设计

热风循环温控系统主要应用于干燥炉中,为被干燥对象提供所需的高品质温控环境。目前,大多数干燥炉的温度控制偏差在5℃以上,同时热气流不均匀造成不同区域的干燥效果不尽相同。通过对以往干燥炉温控系统的总结与优化,提出了一种更为精确、全面的控制方案。该热风循环温控系统主要包括温控系统与风机系统两大部分,通过优化的温控算法整合成PID 温控调节模块以实现温度的快速准确响应;同时引入风机系统,优化机械结构设计来改善气流的均匀性。通过温控系统与风机系统的有效整合,实现了分布均匀、温度可控的干燥环境。经过实际测试使用,该系统达到了设计要求,为干燥炉中温控系统的设计提供了一种可靠地选择。     

用于人体呼气检测中CH4气体检测的激光器温控系统设计

人体呼气检测是一种便捷有效的临床诊断手段,通过检测人体呼出气体中CH₄浓度能够实现消化科、内分泌科等领域的疾病的无损检测。使用TDLAS技术进行人体呼气检测是一种精确、便捷的检测方法。针对TDLAS型CH₄气体检测系统,本文设计了基于FPGA的激光器温控系统。系统选用XC6SLX25为主控芯片,主控制器通过模数转换芯片AD7691实时获取激光器的温度,将实际温度与设定温度进行数字PID运算后,改变数模转换电路输出的电压控制TEC驱动芯片AND8835实现对激光器温度的控制。经过试验测试,该温控系统可以高效、精确、快速的对激光器进行温度控制,控温精度达到±0.01℃。     

全自动太阳光度计温控系统设计及测试

针对温度效应会影响太阳光度计观测结果且温度校正系数难以获取等问题, 设计了一种基于热电制冷器 (TEC) 的全自动太阳光度计温控系统。介绍了自研全自动太阳光度计的整体设计, 特别是温控系统设计, 并分析了温 度对探测器响应的影响。最后对该全自动太阳光度计进行了野外测试, 在合肥地区与商用仪器CE318 进行了同步观测 比对, 测试结果表明全自动太阳光度计反演的气溶胶光学厚度与CE318 校正后的结果一致, 偏差在0.01 以内;在敦煌 地区的长期测试结果表明, 在温度变化较大的长期野外观测中, 全自动太阳光度计温控系统均保持在 (25 ± 0.2) ℃内, 验证了温控系统设计的有效性和可靠性。     

DPSSL激光器的高精度温控电路设计与实现

针对温度变化对于DPSSL激光器工作波长及稳定性的影响问题,提出了一种基于TEC和专用控制芯片LTC1923的温控方案,设计了温控电路及其保护电路,实现了DPSSL工作温度的精确控制。首先分析了DPSSL温控指标需求和TEC热电制冷原理,阐述了温控系统组成及原理;然后详细介绍了温控电路及其保护电路的设计,讨论了防电磁干扰措施及注意事项;最后针对某型DPSSL激光器负载,测试了温控系统的稳态误差、超调量等指标;实验数据显示,该温控系统稳态误差小,控制精度达±0.01℃,能保证DPSSL高稳定性工作。     

用于激光稳频的精密温控系统设计

单块非平面环形激光器可用于产生单频激光。该激光器的频率随温度漂移系数理论值为- 2. 6GHzP℃。设计了一套精密温控装置,对该单频激光器温控以实现稳频。采用单片机结合PID 模块的方法构造温控系统,实现了32 ℃范围内±0. 01 ℃的控温精度,激光频率稳定性达到50MHz ,在此基础上进行了激光器温度调谐试验研究。上述方法构建的温控系统可以提高控制精度并大大缩短调试周期。     

基于MSP430F449的半导体激光器温控系统设计

为了改善传统的半导体激光器温度控制系统体积大、噪音大且精度有限等缺点,研制开发了一种基于MSP430F449单片机与DS18B20数字温度传感器的半导体激光器温控系统。结合PID控制算法,利用PWM脉宽调制,控制热电制冷器的驱动电流,实现对激光器的恒温控制。实验表明,该系统温控精度优于±0.1℃,能够为半导体激光器提供稳定的温度环境。     

全固态单频绿光激光器高精度数字温度控制系统的研究

研制开发了一种基于TMS320F28069嵌入式DSP控制模板的高精度数字温度控制系统,该系统结合变速积分PID控制算法,利用高分辨率脉宽调制(HRPWM)技术,控制热电制冷器(TEC)的驱动电流。针对热敏电阻在高温和低温时温度系数的区别,采用了不同方式的温度检测电路。该系统同时含有三路独立的常温控温模块,在10℃~40℃温控精度为±0.0045℃,一路高温控温模块,在120℃~160℃温控精度为±0.005℃。将该系统用于控制全固态连续单频绿光激光器,在输出功率高达11.07 W时功率波动仅为±0.33%。     

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.     

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.     

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.     

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.     

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.     

Teleportation of an arbitrary unknown N-qubit entangled state under the controlling of M controllers

A new quantum protocol to teleport an arbitrary unknown N-qubit entangled state from a sender to a fixed receiver under M controllers(M < N) is proposed. The quantum resources required are M non-maximally entangled Greenberger-Home-Zeilinger (GHZ) state and N-M non-maximally entangled Einstein-Podolsky-Rosen (EPR) pairs. The sender performs N generalized Bell-state measurements on the 2N particles. Controllers take M single-particle measurement along x-axis, and the receiver needs to introduce one auxiliary two-level particle to extract quantum information probabilistically with the fidelity unit if controllers cooperate with it.     

Diode-end-pumped Nd:YVO4/LBO lasers with 4.2W continuous-wave output at 457 nm

A continuous-wave (CW) 457 nm blue laser operating at the power of 4.2 W is demonstrated by using a fiber coupled laser diode module pumped Nd: YVO4 and using LBO as the intra-cavity SHG crystal With the optimization of laser cavity and crystal parameters, the laser operates at a very high efficiency. When the pumping power is about 31 W, the output at 457nm reaches 4.2 W, and the optical to optical conversion efficiency is about 13.5% accordingly. The stability of the out putpower is better than 1.2% for 8 h continuously working.     

A rigorous proof of MIMO channel capacity’s increase with antenna number

It is well known that adding more antennas at the transmitter or at the receiver may offer larger channel capacity in the multiple-input multiple-output（MIMO） communication systems. In this letter, a simple proof is presented for the fact that the channel capacity increases with an increase in the number of receiving antennas. The proof is based on the famous capacity formula of Foschini and Gans with matrix theory.     

Call for Papers

正Wireless Body-area Networks The last decade has witnessed the convergence of three giant worlds:electronics,computer science and telecommunications.The next decade should follow this convergence in most of our activities with the generalization of sensor networks.In particular with the progress in medicine,people live longer and the aging of population will push the development of wireless personal networks