Pre-filtering Effect in an Iterative Deconvolution Method and Its Application to Signal Recovery in Fiber-Optic Distributed Temperature Sensors

The signal quality of a fiber-optic distributed temperature sensor based on optical time domain reflectometry (OTDR) is improved using a pre-filtering technique in the iterative deconvolution method. Investigation of the performance is proposed using iteration conditions in which recovery rate of the signal-component is equal to that of the unfiltering technique. The recovered signal in the pre-filtering technique gives a good signal-to-noise ratio (SNR), 3 times of the unfiltered signal. Consequently, improvements in the OTDR signal with SNR of from 10 to 100 are obtained under the iterations for both distance and temperature resolutions.     

Fabrication of Spot Size Converters for Optical Chemical Sensors by Distributed-Field-Assisted Ion-Exchange

We propose a new method for fabricating optical waveguides with nonuniform thickness by controlling the electrical field distribution during the field-assisted ion-exchange. We refer to this method as distributed-fild-assisted ion-exchange. The distribution of the intensity of the electrical field was simulated for different electrode configurations, and was compared with experimental diffusion depth distribution of K⁺—Na⁺ exchange in sodalime slide glass. A unique bath was designed for the distributed-field-assisted ion-exchange. Using a three-electrode configuration, we obtained, for instance, a 2 cm-long spot size converter with thickness changes of from 12 μm to 2 μm. This technique can be used to fabricate waveguides for optical chemical sensors.On leave from State Key Laboratory of Transducer Technology, Institute of Electronics, Chinese Academy of Sciences, Beijing, China 100080.     

Temperature Characteristics of Vibrating Type Sensor Using Micromachined Optical Fiber-Tip

An optical sensor using a quartz core microcantilever was fabricated by etching clad layer from optical fiber. The temperature dependence of the resonance frequency of this sensor was measured in atmosphere and water. The temperature coefficient of the resonance frequency in water was 1.3×10⁻³/°C, which was about one order larger than that (2.3×10⁻⁴/°C) in atmosphere. This was caused by increase of additional mass due to temperature dependence of the viscosity of water, while, the increase of the resonance frequency in atmosphere was caused by temperature dependence of Young’s modulus of the quartz core. These results were evaluated theoretically using a “string-of-beads” model.     

衍射微透镜列阵在Shack-Hartmann波前传感器中的应用

菲涅耳衍射微透镜列阵是目前广泛应用的衍射光学元件之一,它是基于衍射原理,由计算机设计,并通过微细加工技术制作成的.本文介绍了8相位台阶菲涅耳衍射微透镜列阵的制作方法,并描述了一个用16×16微透镜列阵形成的小型 Shack-Hartmann 波前传感实验系统,用该系统可对入射波前进行测量和重建.     

光电惯性技术的发展及对策研究

本文主要就激光陀螺、光纤陀螺、半球谐振陀螺、石英音叉陀螺等光电惯性传感器的发展及应用进行了介绍。并对兵器行业应用和发展光学惯性器件提出建议。     

自适应光学系统对大气湍流补偿的有效性分析

从伺服控制系统的角度分析了自适应光学系统的闭环噪声、大气湍流引起的误差以及系统的总体误差，并在此基础上对自适应光学系统的有效性、系统的最佳带宽选取及系统的极限工作能力进行了分析，对已经建立的２．１６米望远镜红外自适应光学系统给出了分析结果曲线。     

传感器测温实验装置的研制

本文介绍了一个新型物理实验装置,把传感器引入了实验教学。此项实验物理方法丰富且具有设计性质。     

金属线膨胀系数测定实验的改进及进一步研究

为了更好地研究金属线膨胀系数在一定温度区间的变化情况,并进一步研究在加热过程中,待测金属热应力、热应变的变化规律,本文在传统的蒸汽喷射加热仪的基础上,组合运用了粘滞系数实验、表面张力实验以及温度传感器实验中的部分实验仪器,测量并计算了相关的物理量,得到了相关性较理想的拟合直线,并通过对比实验进一步论述了该方法的可行性。     

空间光学遥感器主镜加工过程中疲劳寿命研究

针对空间光学遥感器主镜镜面加工过程中,磨盘与主镜间磨削动作往复运行引起的主镜柔性支撑结构疲劳寿命问题,通过建立主镜组件的有限元模型,利用MSC.Fatigue软件按应力-寿命(S-N)法对主镜组件进行了疲劳寿命分析,确定了支撑结构的薄弱部位,并对仿真过程进行了误差分析,讨论了影响仿真结果的各个因素.对比热真空试验和动力学试验前后主镜镜面面型数据,验证了支撑结构加工、设计参量的合理性.通过疲劳寿命仿真分析,可以有效预示光学结构在加工过程中的疲劳情况,为空间光学遥感器结构的设计、加工提供理论依据和参考.     

基于MSP430单片机的自动灌溉演示装置

介绍了基于MSP430F149单片机的自动灌溉演示系统的软硬件设计.该系统通过单片机控制温湿度传感器和光强传感器,实现对环境相对湿度、温度、光强实时采集与处理,演示自动灌溉植物.