All-Optical Bypass-Exchange Switches

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光栅位移激光多普勒遥测技术的研究

研究了利用运动光栅的多普勒效应进行切向位移的遥测技术。提出了测量光路，采用声光调制器作为分光和频移器件并用于鉴向，实现了５０ｍ的远距离光栅位移遥测。达到测量分辨率０．８μｍ，光栅位移４０ｍｍ，最大累积误差优于３４μｍ。并用理论分析和实验，证明了远距离目标的焦深及其计算方法，导出了计算公式。     

WDM多纤环网的优化设计

本文讨论了WDM多纤环网(MFR)的优化设计问题,为解决该问题提出了新的整数线性规划公式.所采用的优化目标是最小化平均结点端口数目,以此为优化目标可以保证所设计的多纤环网具有最大的经济有效性.利用所提出的算法,我们定量分析了采用不同路由方案(波长通道和虚波长通道)的几种MFR结构(单向和双向)的网络性能.本文所获得的结论可作为选择合适MFR结构的参考.     

基于BP神经网络的波长扫描光纤干涉仪多目标信号处理技术

本文提出了一种适用于波长扫描光纤干涉仪多目标绝对距离测量的方法.这种方法将神经网络与数字滤波器等技术相结合,具有超过传统FFT方法的目标分辨极限的分辨能力,可以工作在低的信噪比下.这意味着可以降低对半导体激光器输出功率和扫描波长范围的要求.计算机仿真实验验证了这种方法的性能.     

速度调制分子离子激光光谱技术的理论研究

介绍了速度调制光谱对分子离子测量过程中的一些基本问题,运用朗之万运动方程导出了离子在交流电场中的漂移速度表达式;在小调制度近似下,给出了速度调制谱线的解析表达式,表明谱线的基本线型为高斯线型的一次微分线型、强度与调制度成正比;还讨论了调制电场对谱线的影响。得到的结论可用于实验参数的选择及等离子体的诊断等方面。     

光纤零色散波长的精确测量

提出了一种测量单模光纤零色散波长的新方法,即让可调谐的连续波（波长λｓ）和波长λｐ位于光纤正常色散区的泵浦脉冲串在光纤中共同传输,交叉相位调制与群速度色散的相互作用可使得连续波的强度得到调制。对连续波λｓ进行调谐,若连续波被调制成亮脉冲,则表明λｓ位于光纤负色散区;若连续波被调制成暗脉冲,则表明λｓ位于光纤正色散区;若连续波的强度不能被调制,则表明λｓ位于光纤的零色散波长λ０附近。利用这一方法对长度为０．９８ｋｍ的色散位移光纤的零色散波长进行了测量,测量精度可达０．５ｎｍ。     

PZT相位调制器温度漂移的控制

在光纤陀螺中,ＰＺＴ相位谳制器受温度变化影响会导致陀螺输出信号漂移。本文就这个问题提出一种解决方案,并通过实验进行验证。     

光网络中光纤光栅构成的波长分插复用器理论及进展

本从光网络角度详细叙述、分析了各种光纤光栅构成的波长分插复用器技术的发展及理论,并指出了不同种类分插复用器各自适用的范围,表明了光纤光栅构成的波长分插复用器在光网络中的重要性。     

Fractional time-varying energy distributions of ECG signals

We introduce here fractional Cohen class of time-frequency distributions (FCCTFDs) containing fractional modulations which is kernel of fractional Fourier transform (FFT). The fractional modulation depends on angular parameter α and can be interpreted as a rotation by an angle α in time-frequency plane. This distribution promotes to track time-variant energy of a biological signals and represents it in time-frequency domain. It uses the fractional ambiguity function (FAF) of signal multiplied by a suitable kernel which is designed for the biological signals generally having multi-non-stationary components. This result improves and generalizes some of the previous time-frequency distributions derived in the literature.     

An experimental study of circular sand–water wall jets

Laboratory experiments were carried out to study the effects of sand particles on circular sand–water wall jets. Mean and turbulence characteristics of sand particles in the sand–water wall jets were measured for different sand concentrations c_o ranging from 0.5% to 2.5%. Effects of sand particle size on the centerline sand velocity of the jets were evaluated for sand size ranging from 0.21 mm to 0.54 mm. Interesting results with the range of measurements are presented in this paper. It was found that the centerline sand velocity of the wall jets with larger particle size were 15% higher than the jets with smaller particle size. Concentration profiles in the vertical direction showed a peak value at x/d = 5 (where x is the longitudinal distance from the nozzle and d is the nozzle diameter) and the sand concentration decreased linearly for x/d > 5. Experimental results showed that the turbulence level enhanced from the nozzle to x/d = 10. For sand–water wall jets with a higher concentration (c_o = 1.5–2.5%), the turbulence intensity became smaller than the corresponding single-phase wall jets by 34% due to turbulent modulation. A modified logarithmic formulation was introduced to model the longitudinal turbulent intensity at the centerline and along the axis of the jet.