一种便携式多通道精密测温仪

介绍了利用数字式温度传感器 DS1 6 2 4构成的多路温度测量仪器。它具有线路简单 ,测量精度高的优点 (在 - 5 5～ 1 2 5°C内 ,精度优于 0 .0 5°C) ;带有计算机接口 ,能够实现长时间连续测量。     

New Optical Power Meter for Optical Fiber Transmission System Applications

This paper describes a design and the characteristics of a new optical power meter for 0.8-?m wavelength region optical fiber transmission systems. Features of this optical power meter are high sensitivity (-80 dBm), high stability (±0.005 dB at > -65 dBm), and small deviation against the plug rotation inside the receptacle (±0.02 dB). The SNR design method presented is useful in high sensitivity and high stability optical power meter design.     

Editorial Optical Fiber Sensor Technology and Applications

The forty-seven articles in this special issue focus on optical fiber sensor technology and applications.     

Defect Engineering for Fuel-Cell Electrocatalysts

The commercialization of fuel cells, such as proton exchange membrane fuel cells and direct methanol/formic acid fuel cells, is hampered by their poor stability, high cost, fuel crossover, and the sluggish kinetics of platinum (Pt) and Pt-based electrocatalysts for both the cathodic oxygen reduction reaction (ORR) and the anodic hydrogen oxidation reaction (HOR) or small molecule oxidation reaction (SMOR). Thus far, the exploitation of active and stable electrocatalysts has been the most promising strategy to improve the performance of fuel cells. Accordingly, increasing attention is being devoted to modulating the surface/interface electronic structure of electrocatalysts and optimizing the adsorption energy of intermediate species by defect engineering to enhance their catalytic performance. Defect engineering is introduced in terms of defect definition, classification, characterization, construction, and understanding. Subsequently, the latest advances in defective electrocatalysts for ORR and HOR/SMOR in fuel cells are scientifically and systematically summarized. Furthermore, the structure–activity relationships between defect engineering and electrocatalytic ability are further illustrated by coupling experimental results and theoretical calculations. With a deeper understanding of these complex relationships, the integration of defective electrocatalysts into single fuel-cell systems is also discussed. Finally, the potential challenges and prospects of defective electrocatalysts are further proposed, covering controllable preparation, in situ characterization, and commercial applications.     

光纤的接续技术

光纤的接续技术有两种 :一种是熔接技术 ,另一种是机械拼接技术。光纤熔接技术是利用光纤熔接机进行高压放电使待接续光纤端头熔融 ,合成一段完整的光纤。光纤机械拼接技术是利用弹簧夹将待接续的光纤端头夹紧 ,达到紧密连接的目的。文章对此两种接续方法作了较详细的介绍。     

Miniaturized Optical Fiber Sensor Interrogation System Employing Echelle Diffractive Gratings Demultiplexer for Potential Aerospace Applications

To enable the application of optical fiber sensors to aerospace vehicles, the sensor interrogation or data acquisition system has to meet small size and low weight requirements. This paper presents the developmental work of an echelle diffractive gratings (EDGs) demultiplexer-based optical fiber sensor interrogation system. The operation principle of this system and its application to fiber Bragg grating (FBG) sensor interrogation are presented. The experimental results have shown that the developed interrogator (not including the electronic controller) weighs less than 60 g and provides better than 1 pm measurement resolution and better than plusmn10 pm measurement accuracy.     

光纤化学传感器的研究及其在环境分析中的应用

本文综述了光纤化学传感器的特点、工作原理、类型及各类光纤化学传感器(气敏、pH、金属离子和有机化合物等)的研究进展及其在环境分析中的应用,分析了近年来光纤化学传感器的技术发展和应用趋势。     

Optical Fiber Dual-Reflectometer for Accurate Measurements

In order to measure the reflection coefficients of opt fiber components as accurately as possible, a new "dual-reflectometer" method is proposed. This method is capable of eliminating the major systematic errors in incoherent continuous-wave reflectometers. Experiments have been made using a measurement system with a light-emitting diode (LED) and graded-index multimode fibers. Experimental results show the effectiveness of the method.     

用于短距离通信的塑料光纤技术

介绍了塑料光纤的开发历史和现状,从短距离通信的角度,介绍了聚甲基丙烯酸甲酯（ＰＭＭＡ）的塑料光纤,全氘化塑料光纤和全氟化塑料光纤的损耗,大数值孔径和小数值孔径阶跃型塑料光纤以及渐变型塑料光纤的带宽。另外,介绍了用于高速塑料光纤通信系统的光源和光检测器及其开发现状。     

The Development of a Practical,Drift-Free,Johnson-Noise Thermometer for Industrial Applications

Johnson noise thermometers measure a phenomenon that is directly linked to thermodynamic temperature by a fundamental physical law. The measurement of Johnson noise therefore offers the prospect of realizing a drift-free thermometer. Despite previous attempts to produce a practical Johnson noise thermometer for industrial applications, the technique is currently used only in niche research applications to explore discrepancies between practical temperature scales and thermodynamic temperature, or to determine Boltzmann’s constant. This has largely been due to the historical use of switched correlators to measure Johnson noise, which limits the sense resistance and measurement bandwidth that can be employed. This constraint limits the Johnson noise signal to levels near the limits of measurement. A new technique that eliminates switching and thereby allows the use of much higher sense resistances and bandwidths to increase the Johnson noise signal is presented. The signal power achieved is significantly higher than for systems using a switched correlator. Results so far indicate that measurement performance is compatible with the requirements of industrial applications. Specifically, uncertainties of \({<}0.3 \, {^{\circ }}\hbox {C}\) (95 % confidence) were demonstrated for measurements near ambient temperature with a measurement time of only 7 s.     

蓝宝石单晶光纤高温传感头的高温损伤机制

揭示了蓝宝石单晶光纤高温传感头在高温下的性能劣变现象,指出光纤表面在高温下的永久损伤是产生性能劣变的主要原因。通过对光纤表面的显微分析,明确了损伤的主要机制为外部杂质在高温下与光纤表面的相互作用。并由此确认特殊的光纤表面保护可以保证蓝宝石单晶光纤高温传感头在高温下的稳定工作。     

基于光纤光栅技术的新型光子器件及其在动态可配置波分复用光网络中的应用

报道了光纤光栅外腔激光器、基于可调谐光纤光栅的动态可配置分插复用器(OADM)和全光波长转换器等在全光通信网中有应用潜力的新型光子学器件的实验结果，演示了这些器件的功能，基于这些器件建立了4路符合ITU—T波长标准，间隔为1．6nm的具有动态波长路由、全光波长转换及光信号实时监控功能的密集波分复用光网络演示系统。     

Trilobal Polyimide Fiber Insulation for Cryogenic Applications

Recent measurements have shown a record-breaking low thermal conductivity λ_total of less than 0.25 × 10⁻³ W·m⁻¹·K⁻¹ at temperatures of 120 K for an evacuated sample consisting of polyimide fibers with a trilobal fiber cross section. Existing models for the heat transport in fiber insulations cannot sufficiently describe fiber insulations consisting of fibers with non-cylindrical cross sections. In this article, a modification for the model for cylindrical fibers will be presented. The modifications for the trilobal cross section of the fiber will be explained and compared to the original cylindrical model. The results of the theoretical calculations will be discussed in comparison to experimental results of measurements performed with a guarded hot-plate apparatus at temperatures in the range from 120 K to 420 K.     

国外光纤光纤带和带状光缆技术的最新发展

综合介绍了近年国外关于低衰耗的色散补偿光纤,非零色散位移光纤,用于恶劣环境的碳涂覆和氮化硅涂覆光纤的研究;光纤带制造技术包括光纤带的结构、涂层、性能、生产工艺,大芯数光纤带状光缆包括层绞式松管、中心松管式、骨架式、干缆芯带状光缆的设计制造技术的最新进展。     

光纤传感式材料折射仪

本文介绍了一种基于菲涅尔公式和光纤技术研制的新型宝石折射仪。     

Polycrystalline Zinc Selenide for IR Optical Applications

Data are summarized on the preparation and properties of polycrystalline ZnSe for passive IR elements. The influence of preparation conditions on the structure, optical properties, and mechanical strength of ZnSe is analyzed in detail. Particular attention is paid to the effect of impurities and intrinsic defects on the optical performance of ZnSe.     

使用SOA的一种多信道全双工光纤无线通信系统

提出一种新的在中心站使用单个光源的全双工光纤无线通信系统.该系统在中心站基于半导体光放大器(SOA)的交叉增益调制效应,产生用于下行链路传输的40 GHz毫米波信号.下行链路的基带信号仅调制于一个光载波边带上,而上行链路数据在基站中调制于来自中心站的光载波并发射回中心站.在40k m的传输距离内,双向误码特性都没有基底,下行链路功率代价为3.5 dBm,上行链路功率代价小于0.5 dBm,成功地实现了速率为2.5 Gbit/s的双向链路传输.系统在远距离传输中显示出较好的性能,在高射频波段和多信道全双工系统中有着重要的应用价值.