基于扩径光纤锥马赫曾德尔干涉仪的位移传感

以直线形光纤马赫曾德尔干涉仪作为滤波器件,掺铒光纤作为增益介质的环行腔光纤激光器实现位移传感。构成该马赫曾德尔干涉仪的扩径光纤锥由光纤熔接机制作而成。随着两个应力调节支架距离的减小,干涉仪发生弯曲,输出的波峰向短波长方向移动,最大敏感度为4.49 nm/mm,消光比大于50 dB。扩径光纤锥的引入使得光纤在弯曲时能够保持基本一致的弯曲度,并且相比其他结构强度更高,不容易发生断裂。同时,该结构的制作所需材料便宜,制作过程简便,有利于工程应用。     

中科院西安光机所荧光光纤温度传感器及测量系统项目取得新进展

由中科院西安光学精密机械研究所瞬态光学与光子技术国家重点实验室研制、具有完全自主知识产权的荧光光纤温度传感器及测量系统近日完成小批量生产研究,并已提供给智能电网、生物医疗、石油化工、工业微波、电源管理、科学研究和军事国防等领域十多家单位应用,受到用户好评。     

High finesse ring resonators made by silver ion exchange in glass

We report the fabrication of single tap ring resonators made by thermal silver ion-exchange in various types of glass substrates. The highest finesse achieved was 55 with an efficiency of 32 percent. We systematically measured losses arising from different sources such as intrinsic absorption in the glass and scattering from side wall roughness arising from the mask fabrication technique. All data was measured atlambda = 0.6328 mum.     

Hydroxyl group formation caused by hydrogen diffusion into optical glass fibre

Transmission loss increase of optical glass fibre caused by hydrogen diffusion is measured as a function of temperature and partial pressure of hydrogen gas. The activation energy of hydroxyl group formation from the diffused molecular hydrogen was found to be 15.9 kcal/mole. Also the hydroxyl absorption loss increase at 200°C was found to be proportional to the square root of the partial pressure of hydrogen gas.     

Directed diffusion for wireless sensor networking

Advances in processor, memory, and radio technology enable small and cheap nodes capable of sensing, communication, and computation. Networks of such nodes can coordinate to perform distributed sensing of environmental phenomena. We explore the directed diffusion paradigm for such coordination. Directed diffusion is data-centric in that all communication is for named data. All nodes in a directed-diffusion-based network are application aware. This enables diffusion to achieve energy savings by selecting empirically good paths and by caching and processing data in-network (e.g., data aggregation). We explore and evaluate the use of directed diffusion for a simple remote-surveillance sensor network analytically and experimentally. Our evaluation indicates that directed diffusion can achieve significant energy savings and can outperform idealized traditional schemes (e.g., omniscient multicast) under the investigated scenarios.     

Solar cells in bulk InP,made by an open tube diffusion process

This paper describes a simple open tube diffusion process for the fabrication of n⁺-p solar cells in indium phosphide. Large area cells (>0.25 cm²) have been made by this process, with a photovoltaic conversion efficiency of 16.3% under simulated AM1 conditions of illumination. The external quantum efficiency of these cells has been measured, and is approximately 68% without an antireflective (AR) coating, and 100% with a 750 Å coating of silicon monoxide.An ideality factor of 1.1 and a saturation current density of 8×10⁻¹⁵ A/cm² have been observed for these cells. These are the lowest (best) values reported to date for diffused structures in bulk InP.     

高双折射单模光纤温度传感器

1 引言 偏振干涉型光纤温度计的灵敏度介于干涉型和强度型之间。典型的干涉型光纤温度传感器是以光纤耦合器为核心,构成Mach-Zehnder的一类干涉仪,它是以两根光纤分别作为干涉仪的测量臂和参考臂。虽然灵敏度高,但由于外界环境因素对参考臂的干扰极为敏感,以致在一般条件下,难以正常工作。文献[2]则以一根高双折射光纤中正交偏振模HE_(11)对外界因素有不同相移,使这两个模式的光发生干涉,从而能有效地克服外界因素的干扰。本文利用时间相     

WSN中基于定向扩散协议路由算法的研究

定向扩散协议作为一种经典的以数据为中心的无线传感网络的路由协议,得到了广泛的认可。但是在复杂质询的应用中,定向扩散协议采用的泛洪质询算法的能效性非常低,本文在此基础上提出了一种改进算法,可以将复杂质询分成若干个子质询,节点在收到质询消息后,可以先通过向d跳之内的相邻节点收集信息来解决质询消息。并将改进算法与传统的泛洪质...     

致密扩散障型氧传感器扩散机理的研究

为研究致密扩散障型氧传感器的扩散机理,采用ScSZ基电解质和La0.8Sr0.2MnO3(LSM)混合导体材料,利用Pt浆粘结法,制备了致密扩散障型极限电流氧传感器,并分别测试了其在(O2)为0.81%～22.43%及温度873～1023K时的电流-电压曲线。通过实验分析,极限电流IL与?(O2)的关系更符合Knudsen扩散模型,建立在固体离子扩散方式下的理论,可对IL与温度T之间呈现出来的规律进行合理的解释。     

Software agent-based directed diffusion in wireless sensor network

In an environment where node density is massive, placement is heterogeneous and redundant sensory traffic is produced; limited network resources such as bandwidth and energy are hastily consumed by individual sensor nodes. Equipped with only a limited battery power supply, this minimizes the lifetime of these sensor nodes. At the network layer, many researchers have tackled this issue by proposing several energy efficient routing schemes. All these schemes tend to save energy by elevating redundant data traffic via in-network processing and choosing empirically good and shortest routing paths for transfer of sensory data to a central location (sink) for further, application-specific processing. Seldom has an attempt been made to reduce network traffic by moving the application-specific code to the source nodes. We unmitigated our efforts to augment the node lifetime within a sensor network by introducing mobile agents. These mobile agents can be used to greatly reduce communication costs, especially over low bandwidth links, by moving the processing function to the data rather than bringing the data to a central processor. Toward this end, we propose an agent-based directed diffusion approach to increase sensor node efficiency and we present the experimental results.     

Displacement current sensor for contact and intermittent contact scanning capacitance microscopy

In this study a displacement current capacitance sensor (DCCS) for scanning capacitance microscopy (SCM) is introduced. It can be used for both intermittent contact (IC) and contact-SCM operation. Based on I/V conversion and subsequent lock-in amplification a displacement current can be detected and used as a measure for dopant concentration. Therefore a periodic variation of the AFM tip substrate capacitance is required. This can be achieved either by a periodic tip oscillation (IC-SCM) or an applied AC voltage between tip and sample (contact-SCM). The advantage of the DCCS is the linearity, which makes it possible to detect absolute dopant concentrations.     

Al2O3薄壁管FBG高温高压传感器性能研究

用有限单元方法建立了Al2O3薄壁管模型,分析了模型在外部受到均匀压力时的应力应变关系.借助ANSYS软件计算出模型的应力和应变.以上述薄壁管为衬底,设计制作了耐压为0～45 MPa、温度为-10～300 ℃、压力灵敏度系数为0.042 6 nm/MPa和温度灵敏度系数为0.011 2 nm/℃的光纤Bragg光栅(FBG)高温、高压传感器,并对其性能进行了测试.结果表明,传感器的压力、应变灵敏度的有限元分析结果与实验测试结果非常吻合.     

Filtering approaches to accelerated consensus in diffusion sensor networks

The main objective in distributed sensor networks is to reach agreement or consensus on values acquired by the sensors. A common methodology to approach this problem is using the iterative and weighted linear combination of those values to which each sensor has access. Different methods to compute appropriate weights have been extensively studied, but the resulting iterative algorithm still requires many iterations to provide a fairly good estimate of the consensus value. In this paper, different accelerating consensus approaches based on adaptive and non‐adaptive filtering techniques are studied and applied on the problem of acoustic source localization using the adaptive projected subgradient method. A comparative simulation study shows that the non‐adaptive polynomial filters based on Newton's interpolating polynomials and semi‐definite programming can provide more accelerated consensus and better estimation accuracy than adaptive filters evaluated using constrained affine projection algorithm or stochastic gradient algorithm provided that the network topology is known beforehand. Copyright © 2013 John Wiley & Sons, Ltd.     

Low temperature diffusion process for fabricating optical waveguides in glass

A thermal evaporation source provides a vapour stream of metallic dopant directed at a glass substrate. The metal atoms thermally diffuse into the glass surface and are accelerated through the substrate by an electric field. The doped glass forms an optical waveguide stripe.     

Design of a novel chip on glass package solution for CMOS image sensor device

This paper presents a chip-on-glass (COG) package solution for CMOS image sensors based on highly precise and reliable bumping and flip-chip bonding techniques. The package is fabricated using three core techniques, namely the damage-free image sensor bumping technique, the wafer form glass substrate patterned technique, and the damage-free flip-chip bonding technique. Since the proposed package concept is new, the effects of the package geometry and material properties on the package reliability are uncertain in the initial design stage. A three-dimensional nonlinear finite element model of the proposed CMOS image sensor package is created. In the simulations, the applied thermal load is cooled from 200 °C to ambient temperature (25 °C) to model the thermal deformation and warpage of the package during the practical ACF assembly cooling process. The design parameters influencing the reliability of the package, i.e. the material properties of the ACF, the thickness of the image chip and the thickness of the optical glass are investigated. Two control levels are specified for the chip, glass, and ACF factors and a 2³ factorial design is created to determine the appropriate combination of material properties and geometric size. It is found that the glass thickness and the ACF properties significantly affect the thermal deformation of the package, while the chip and glass factors, and the interaction between them, significantly affect the warpage. Regression models are developed to perform a series of surface response simulations. Using the developed statistical tests and regression models, suitable material selection criteria and geometric sizes can be specified to satisfy various reliability considerations in the initial design stage.     

Fiber ring laser with flint glass fiber and its sensor applications

A new fiber ring laser has been proposed which is composed of a laser diode amplifier, a flint glass fiber as a sensing element, and a Faraday cell as a bias element, and applied to a frequency-domain sensor in which nonreciprocal effects such as current or rotation can be measured from a frequency change in the beat signal. A sign of current or rotation direction can be determined and a lock-in phenomenon is avoided owing to the bias element     

Fabrication and performance of low loss optical components made byion exchange in glass

Passive optical components made by photolithography with ion exchange in glass have been developed. The technology used to fabricate these components is described, and their performance characterization is discussed. It is shown that this technique produces highly uniform low-loss devices     

物理所成功制备微纳米金属玻璃纤维

最近,中科院物理研究所／北京凝聚态物理国家实验室（筹）汪卫华课题组易军等人发展了一种新的工艺方法,成功制备出金属玻璃纤维。相关结果发表在Adv Eng Mater12,1117（2010）上。     

玻璃平面波导的热键合制备与界面扩散研究

铒镱共掺磷酸盐玻璃平面波导在散热和抑制非线性效应方面具有独特优势,可开发作为近红外1.5 μm高平均功率固体激光器的增益介质,具有重要意义。文中应用光胶热键合方法制备铒镱共掺磷酸盐玻璃平面波导,研究了预键合阶梯升温过程对键合质量的影响。通过电子探针表面分析（EPMA）得到键合温度和键合时间对键合界面分子扩散层厚度的影响,并根据Fick第二定律,探讨了一维等效假设下的芯层玻璃中的Yb3+扩散机理,建立了热键合过程中的固-固界面分子扩散模型。最终通过选择最优的热处理工艺参数,得到了键合质量良好且键合强度达到11.63 MPa的芯层厚度为100 μm的三明治结构平面波导。