一种非本征光纤法珀声发射传感系统的研制

针对光纤法珀声发射传感器输出信号衰减与失真问题,设计一种采用改进的双波长稳定技术的传感系统.分析系统工作原理、建立双波长稳定优化模型与设计光电检测前置放大电路.采用1×2密集波分复用器产生两路处于正交状态的输出信号,密集波分复用器(DWDM)滤波波长用优化模型求解.试验结果表明当法珀腔长度变化在0～2 μm范围内,双波长最大正交误差为11%,能够满足光纤法珀声发射传感器工作点的稳定要求.通过对振动与断铅笔芯信号检测,初步验证这种传感系统可用于构件的损伤检测.     

Optical fiber sensing element based on luminescence quenching of silica nanowires modified with cryptophane-A for the detection of methane

An optical fiber sensing element based on luminescence quenching of cryptophane-A/silica nanowires was successfully constructed and used to dynamically monitor methane gas at low concentration below 3.5% (v/v). The optical fiber device was designed to operate via luminescence reflection. The sensing properties of optical sensing element to methane at room temperature were characterized. The sensing element shows an intensive and stable blue luminescence when excited by UV light source at wavelength of 380 nm, and it is efficiently quenched by molecular methane. The response of the sensing element demonstrates excellent linear Stern-Volmer behavior at the fixed wavelength 439 nm within the methane concentration range between 0.1% and 3.5% (v/v). A detection limit of below 0.1% (v/v) is estimated for the methane sensing element. This newly developed methane sensing element has significant advantages over the currently available methane sensors such as fast response and recovery (within seconds), good repeatability, selectivity, and long-term stability.     

基于嵌入式的空间光通信系统前馈补偿系统设计

为满足光通信系统对于目标数据的快速捕获需求,缩小各级通信设备间的动态跟踪误差,设计基于嵌入式技术的空间光通信系统的前馈补偿系统;以并串转换电路作为唯一的电能输出装置,在光通信信号发射模块、波分复用器件、嵌入式光放大器三个通信设备元件的共同调节作用下,确定PWM功率放大器的实时执行能力,达到对前馈型角编码器的调度与应用,实现空间光通信系统前馈补偿结构的搭建;配置Linux嵌入内核的移植协议,多次创建空间光环境下的通信数据根文件,以此为存储标准,计算补偿调制的基础传信率,实现对前馈脉冲波的调制与处理,完成嵌入式通信系统的前馈补偿原理研究;实验结果表明,应用前馈补偿系统后,在光通信参量等于5.0×1011 T、7.0×1011 T、9.0×1011 T的情况下,目标数据的捕获速率均超过7.0 T/mm,满足缩小通信设备间动态跟踪误差的实际应用需求。     

光触发电子测压器的设计

针对现有采用内触发方式的壳体电容式电子测压器,装配过程中壳体电容易受干扰,从而造成误触发或不触发等问题;同时为了获取火炮膛内压力场信息,需要进行膛内多点压力测试,但用内触发方式时间机制难以统一,由此提出了基于爆炸场光信号外触发测压器的设计,通过改造测压器的端盖,设计可靠的光触发电路,利用爆炸场光信号作为采样触发信号,将处理过的与压力信号有关的电信号进行采集并存储到单片机flash中。经模拟实验,该光触发测压器能够准确触发,为解决现有测压器容易误触发,获取膛内多点压力等问题提供了可行的方案。     

On ordered scheduling for optical burst switching

Optical burst switching (OBS) is a promising optical networking paradigm for efficient transport of bursty IP traffic over wavelength division multiplexing (WDM) optical Internet networks. In OBS, the header of a burst is sent in advance of the data burst to reserve a wavelength channel at each optical switching node along the path. The nodes use a scheduling algorithm to assign wavelengths to incoming bursts. Our work is motivated from the observation that existing scheduling algorithms assign a wavelength to a burst when its header arrives at the node. Thus, information about other bursts whose headers arrive later is not available when the scheduling decision is made. This leads to suboptimal scheduling decisions and unnecessary burst dropping. The key idea in our proposed algorithm, Ordered Scheduling, is to defer making the scheduling decision until just before the burst arrival in order to have full knowledge about other bursts. The effectiveness of the proposed algorithm is studied through simulation and the computational complexity and signalling overhead are analysed.     

一种基于温控半导体激光波长扫描的光纤瓦斯测量系统

设计了一种基于温控半导体激光波长扫描的光纤煤矿瓦斯测量系统,通过改变中心波长1653 nm半导体分布式反馈( DFB)激光器的工作温度来扫描半导体DFB激光器的输出波长,在5 nm波长扫描范围内,存在明显的瓦斯气体吸收峰。半导体DFB激光器输出的光注入被测气体室,气体室的输出光携带有瓦斯气体浓度信息,用光电探测器将光信号转化为电信号,再由A/D采集卡采集到信号处理系统,通过对有吸收峰位置的光功率和无吸收峰位置的光功率进行比较,则可计算出瓦斯浓度。该传感系统采用80 mA恒流源驱动半导体DFB激光器,使其输出光强保持不变,其结构简单、灵敏度高。     

Building a 100 Mpixel graphics device for the OptIPuter

Wide area optical lambda networks create new possibilities for data-intensive scientific research and collaboration. One initiative to create novel infrastructure is the OptIPuter project which aims to build a distributed virtual computer using optical networks. At the iGrid2005 venue, an experiment was conducted on how a 100 Mpixel display device in San Diego could be driven by a remote 100 Mpixel graphics device in Amsterdam. The experiment showed the viability of such a setup, thereby validating one specific part of the OptIPuter concept: geographic separation of 100 Mpixel graphics- and display device. A key element in our setup is the use of unreliable communication.     

非接触式光纤法珀微位移检测系统

设计一种采用双波长正交解调技术的光纤法珀检测系统,可用于微位移的检测.系统使用1×2密集波分复用器产生两路处于正交状态的输出信号,密集波分复用器的输出波长采用优化设计方法计算.信号处理采用arctan算法实现微位移信号的解调.实验通过对变化范围为0～0.8 μm的位移进行检测,结果表明该传感系统的灵敏度达到0.468°/nm,非线性度仅为2.3%,可满足实际中微位移检测的需要.     

小波分析在光纤电压传感器采集信号分析中的应用

文章介绍了光纤电压传感器的原理.小波变换为采集的信号分析提供了有力的数学工具.光纤电压传感器传输后的信号,存在着谐波和噪声干扰.利用小波变换对所检测到的电压信号进行了分析.     

基于禁忌遗传算法求解路由和波长分配问题

静态的路由选择和波长分配(RWA)问题是WDM光网络中的一个重要问题,目前常用的处理方法是将RWA问题拆成选路子问题和波长分配子问题.静态RWA问题通常先按某种策略确定建立光路的顺序,然后用启发式算法加以解决.提出通过禁忌遗传算法对光路的建立顺序进行优化,然后用基于爬山算法的启发式算法来求解以波长数最小为优化目标的静态RWA问题.通过对ARPANet等5种实际光网络的仿真表明,提出的算法和文献[5]相比,所用的波长数更少,且大部分优化结果达到最优.     

A novel device of passive and fixed alignment of optical fiber

In the microoptics field, precise alignment is very important to reduce the coupling losses in optical links. In this paper, a novel device of passive and fixed alignment of optical fiber is proposed. The rectangular V-groove formed by one sidewall of SU-8 resist and the substrate is used to position the optical fiber, and the leaf spring with flexure hinge clamps it. The spring is fabricated by the sacrificial layer technique. The clamping force provided by the spring acts on the upper semi-circle of the optical fibers cross section, so that the device need not use the additional cover on the optical fiber to perform the vertical location and the final fixing. It has simple structure and process, and is convenient to assemble and integrate with other microparts. The coupling of two optical fibers using the devices in our experiment has less than 1.5 dB insert loss.     

Optical correlator for recognizing characters printed on paper

Pattern recognition is an example of data processing for which analog processors are well suited. We can optically classify various and complicated patterns in one operation instantaneously. Unfortunately, most information is written or printed on paper. From this reason they are not suited to conventional coherent processing. In this paper a coherent optical processor which is capable of recognizing characters printed on paper is presented. It is based on quasi Fourier holography adapted to diffuse illumination of optical signals. In this case the recognition correctness is diminished a little. The experiments are carried out with conventional print letters.     

光波长路由器中控制信号的优化设计与实现

设计并实现了一种应用于全光波长路由器控制系统的简化的数据链路层控制帧结构，将底层物理层中光波长分配、可控制的虚波长通道和上层数据链路层中的具有服务等级QoS的光链路、具有流量工程的自动光路由和简单网管协议SNMP集成在一个系统。通过实验测试，验证了控制系统的良好性能。     

生存光传输网络的交叉连接模块结构

基于波分复用技术的光传输网络在克服当前网络容量瓶颈的同时又面临网络生存的挑战,它必须快速、有效地恢复因网络故障而受损的工作光路。该文分析了四种基本网络恢复技术以及与之相对应的OXC节点模块结构,即:保留光纤链路方式、保留波长链路方式、保留波长路径方式以及动态波长路径方式;并从光连接恢复时间、网络资源效率和控制复杂度三个侧面比较了不同OXC结构对于网络生存的影响。     

Searching for optimal sensitivity of single-mode D-type optical fiber sensor in the phase measurement

To improve the sensitivity of a single-mode D-type optical fiber sensor, we selected a D-type optical fiber sensor with 4 mm long and 4 μm core thickness made of a single-mode fiber, a Au-coating on the sensor with a thickness range of 15–32 nm, a light wavelength of 632.8 nm, and an incident angle of 86.5–89.5° for different refractive index (1.33–1.40) sensing. These simulations are based on the surface plasmon resonance (SPR) theory using the phase method which shows that the sensitivity is proportional to the refractive index, Au film thickness and lower incident angle on the sensing interface. The sensitivity is higher than 4000 (degree/RIU), and the resolution is better than 2.5 × 10⁻⁶(RIU) as the minimum phase variation is 0.01°. This device is used to detect the refractive index or gas or liquid concentration in real-time. The proposed sensor is small, simple, inexpensive, and provides an in vivo test.     

基于光传输的USB键盘鼠标一体化设计

摘要;为解决通用串行总线USB的传输距离短的问题,提出了一种用光纤传输替代电气传输的方案.该方案通过在USB主机端和USB设备端分别添加一MCU来分别模拟主机和设备的行为,从而实现USB主机和USB设备的隔离,以便可以通过光纤传输来代替电传输.通过键盘鼠标一体化设计实例,验证了该方案具有可行性和实用性.该设计方案已经在实际项目中得到了很好的应用.     

Optical low-coherence reflectometry for a distributed sensor array of fiber Bragg gratings

An optical low-coherent interferometric technology for fiber Bragg grating (FBG) sensor array is described. A series of identical FBGs with low reflectivity form a sensor array. The first FBG of the array works as the reference FBG and the others work as sensing FBGs. Each sensing FBG and the reference FBG can form an in-fiber Fabry–Perot (F–P) interferometer with a specific cavity length. By scanning a home-made optical low-coherence reflectometry, the interference signals corresponding to different sensing FBGs (F–P interferometers) can be obtained and well distinguished. The mismatch in wavelength between the reference FBG and a sensing FBG induced by the measurand around this sensing FBG will cause the decrease of the intensity of the corresponding interference signal. A measurement of temperature is demonstrated and good performance is achieved. Factors limiting the total number of sensing FBGs are also discussed.     

Top-gate ZnO thin-film transistors with a polymer dielectric designed for ultraviolet optical gating

We report on the fabrication of ultraviolet (UV)-sensing top-gate ZnO thin-film transistors (TFTs) with a poly-4-vinylphenol (PVP) polymer gate dielectric on glass substrate. Our top-gate ZnO-TFT showed a field-effect mobility of 0.05 cm²/V s, maximum saturation current of 0.11 μA at a gate bias of 10 V and an on/off ratio of 10³ in the dark. Under UV illumination with a wavelength of 364 nm the ZnO-TFT exhibited 4.7 μA for a drain current (at the same gate bias of 10 V), which is 50 times higher than without UV. Such photo-transistor action appeared more pronounced under a depletion regime of 0 V gate bias and the photo-to-dark current ratio was more than about 10⁴. By adopting this high UV-sensitivity, our inverter device with the top-gate ZnO-TFT and a load resistance well demonstrated its optical gating behavior.     

基于WDM传输网的动态路由算法

波分复用技术(WDM)作为一种公认的最佳光纤扩容技术已被广泛应用在国际和国内长途骨干网上。路由算法与波长分配(RWA)是WDM网中的重要技术之一,评价RWA算法的一个重要标准是网络阻塞率。采用合适的路由算法可以大大降低网络的阻塞率。该文采用一种结合了再生节点选择的动态RWA算法来解决WDM网中的波长路由问题,并通过光纤通道拓扑的优化算法来进一步优化。通过建模仿真,研究了NSFNET网络优化前后阻塞率的变化,仿真的结果证明采用该优化算法可以降低网络的阻塞率。     

Architectures and routing schemes for optical network-on-chips

As indicated in the latest version of ITRS roadmap, optical wiring is a viable interconnect technology for future SoC/SiC/SiP designs that can provide broad band data transfer rates unmatchable by the existing metal/low-k dielectric interconnects. In this paper, we present an interconnection architecture, referred as the wavelength routed optical network (WRON), suitable to build on-chip optical micro-networks. The routing scheme for WRON, using any two of the three routing parameters (the source node address, the destination node address, and the routing wavelength), is generalized in this paper. With WRON as the primitive platform, we further propose a new recursive architecture, the recursive wavelength routed optical network (RCWRON), and it serves as the basis of a redundant architecture, the redundant wavelength routed optical network (RDWRON). The routing schemes for RCWRON and RDWRON are also detailed in this paper.