聚合物光纤在千兆网系统中的应用

介绍了国内近年来聚合物光纤在千兆网系统中应用的最新进展,着重阐述了聚合物光纤的发展和梯度折射率聚合物光纤的传输特性。从光纤入户的实际应用出发,探讨了聚合物光纤走向千兆网系统所要解决的关键技术问题,这些问题的解决对推动国内光纤入户工程具有一定的指导意义。     

High-speed resonant cavity light-emitting diodes at 650 nm

State-of-the-art resonant cavity light-emitting diodes (RC-LEDs) optimized for short-haul communication systems on polymethyl methacrylate (PMMA) plastic optical fiber (POF) are presented. The devices, emitting in the 650-nm wavelength range, are achieving, under different structure and working regime variants, high output power (15 mW), high external quantum efficiency (9.5%), record small-signal modulation bandwidth (f_{-3 dB} UP to 350 MHz), error free back-to-back transmission rates beyond 622 Mb/s, adjustable far-field pattern and good coupling efficiency into step index plastic optical fibers with reasonably large tolerances and without using auxiliary optics. The paper discusses the design concepts, modeling approaches, fabrication issues and performance characteristics of monolithic RC-LEDs emitting at 650 nm     

基于1394b和POF的光电转换实现

在短距离通信领域,针对空间小、节点多、电磁干扰强等环境中信息高速无干扰传输问题,本文提出一种基于IEEE-1394b协议的高速串行光总线的实现,完成了信息传输介质为塑料光纤时,带有光电转换电路的1394b转发器的设计.该设计能够有效降低光传输系统的成本,提高可靠性及可维护性.从PC端光总线系统网络拓扑图中显示的连接,可以看出本文设计的硬件电路满足应用系统的需求.由转发器、SMI接口塑料光纤及1394b PC节点组成的光传输系统可以高速实时传输视频及音频数据.     

Low‐voltage low‐power CMOS receiver front‐end for gigabit short‐reach optical communications

This article presents a new CMOS receiver analog front‐end for short‐reach high‐speed optical communications, which compensates the limited product bandwidth length of 1‐mm step‐index plastic optical fiber (SI‐POF) channels (45 MHz · 100 m) and the required large‐diameter high‐capacitance Si PIN photodetector (0.8 mm–3 pF). The proposed architecture, formed by a transimpedance amplifier and a continuous‐time equalizer, has been designed in a standard 0.18‐µm CMOS process with a single supply voltage of only 1 V, targeting gigabit transmission for simple no‐return‐to‐zero modulation consuming less than 23 mW. Experimental results validate the approach for cost‐effective gigabit SI‐POF transmission. Comparative analysis with previously reported POF receivers has been carried out by introducing a useful figure of merit. Copyright © 2012 John Wiley & Sons, Ltd.     

POF-based interconnects for intracomputer applications

The technology and the optical characteristics of ×8 optical interconnects based on plastic optical fibers (POF's) are presented. The MT-compatible interconnects have been realized by using ribbonized 120-1125-μm multimode step index POF. Two-dimensional POF arrays with a pitch of 250 μm have been fabricated either by using precision drilled PMMA-hole-plates or by embedding the POF's in grooved copper plates and piling them up subsequently. The transmission loss of a 20 cm-long 8×8 interconnect including two 900 bends was 1.5 dB at 650 nm, 3.5 dB at 870 nm, and 4.5 dB at 980 nm     

能量变换器及其最新发展

介绍了20世纪末出现的一种新型的可直接并网的高压发电装备--能量变换器(Powerformer)的基本原理、开发背景、目前现状、技术关键、设计特点和运行特点,并对其发展及应用前景进行了展望.     

渐变型塑料光纤的制备方法分析

渐变型塑料光纤(GI POF)具有芯径大、柔韧性好、易安装、成本低、抗冲击强度高、抗电磁干扰、无电磁辐射、高带宽等特点,成为局域网以及光纤到户的首选材料。GI POF的制备方法有直接挤出法和预制棒拉纤法,本文将对以上两种方法分别加以综述,最终得出制备GI POF的最佳工艺路线。     

Parameters affecting bending losses in graded-index polymer opticalfibers

Radiation losses that occur when bending graded-index polymer optical fibers (POFs) are analyzed as a function of the profile exponent, the light wavelength, the fiber core radius, and the length of the bent section. For this purpose, a ray-tracing model is used, which combines both the generalized Fresnel power transmission coefficients for curved graded-index media and the differential equations that govern the ray paths in highly multimode graded-index fibers. This model is applied to the most recent types of graded-index POF, for which the choice of the core radius and profile exponent is discussed from the point of view of bending losses (the greater the profile exponent and the core radius, the greater the bending losses). The influence of profile exponents different from two is included for the first time     

Wearable Monitoring of Seated Spinal Posture

This work describes the evaluation of a wearable plastic optical fiber (POF) sensor for monitoring seated spinal posture, as compared to a conventional expert visual analysis, and the development of a field-deployable posture monitoring system. A garment-integrated POF sensor was developed and tested on nine healthy subjects. Data from the wearable sensor were compared to data taken simultaneously from a marker-based motion capture system, for accuracy and reliability. Peak analysis of the resulting data showed a mean time error of 0.53 $pm$ 0.8 s, and a mean value error of 0.64 $pm$ 3.1 deg, which represents 14.5% of the average range of motion. Expert determination of transitional (good to bad) posture showed a variation of 20.9% of range of motion. These results indicate that the wearable sensor approximates the accuracy of expert visual analysis, and provides sufficient accuracy of measurement to reliably monitor seated spinal posture.      

新型超高压线路保护监录系统实现

针对超高压线路保护的监录调试方面新增的功能需求,设计开发了一种新型线路保护监录系统。该系统主要包括线路保护的运行监控、故障报告和事件记录文件的上传保存和故障记录数据的分析等功能。同时为满足大信息量的实时和标准归一化传输要求,该监录系统采用IEC60870-5-103规约传输保护数据信息。此外,该监录系统采用了多线程、功能模块化设计等技术实现监测、管理、录波、分析等功能。     

Realization and characterization of 8×8 resonant cavity LEDarrays mounted onto CMOS drivers for POF-based interchipinterconnections

An 8×8 array of resonant-cavity light emitting diodes (RCLED's) emitting at 980 nm and flip-chip mounted onto complimentary metal-oxide-semiconductor (CMOS) integrated drivers, is presented. The RCLED's are optimized for maximal extraction efficiency into the numerical aperture of polymer optical fibers (NA=0.5) and minimal optical crosstalk. Design of the optimal cavity structure is presented, and 8×8 arrays are realized and mounted directly onto standard CMOS chips using a solder reflow technique. The CMOS integrated drivers are designed for high-speed operation and low-power consumption, and are realized in 0.8 and 0.6-μm CMOS technology. The electrooptical modules have been realized and characterized, and over 50-μW optical power coupled to POF at 3-mA drive current is reported. Open eye diagrams at operation speed up to 250 Mb/s are presented. These characteristics are compatible with CMOS integrated low-power receivers     

Multiterabit/s DWDM terrestrial transmission with bandwidth-limiting optical filtering

Wavelength-division multiplexing (WDM) systems based on 40-Gb/s channel bit rate appear as likely successors of current widespread N/spl times/10 Gb/s systems. However, they will provide larger throughputs than N/spl times/10 Gb/s systems only if some specific techniques are implemented, so as to improve the utilization ratio of the optical bandwidth, namely, the information spectral density (ISD). Narrow optical filtering is one such technique. Based on a review of some of our multiterabit/second transmission experiments in terrestrial configurations, we highlight the benefits of optical filtering to reshape the channel spectra. First, we show that vestigial sideband (VSB) narrow filtering of nonreturn-to-zero (NRZ) data makes 0.64-bit/s/Hz ISD possible over long-haul and ultra-long distances, provided that a specific wavelength allocation scheme is implemented. Using this scheme, a record 10-Tb/s capacity is demonstrated over 300 km by applying different data along each of the two polarization axes. However, along a single polarization axis and when channels are packed closer with NRZ-VSB filtering, at 0.8-bit/s/Hz ISD, nonlinear interactions between channels affect system performance and reduce the maximum error-free distance. We show that these interactions can be contained, still using narrow optical filtering, but by resorting to an alternative modulation format, namely, phase-shaped binary transmission.     

基于塑料光纤的用电信息采集系统研究与设计

阐述了塑料光纤（plastic optical fiber,POF）的特点,分析用电信息采集系统对于通信的典型要求,提出了一种基于 POF的全光纤用电信息采集系统的设计方案。此方案结合 POF和石英光纤两种光纤的优势,将二者分别用于本地通信和远程通信,可使智能电表与主站之间实现实时通信,具有可靠性高、功耗低、投资相对较小的优点。对于智能电表集中安装的城区以及电力光纤到户的智能小区,这是一种用电信息采集的理想方案。     

Highly spectral-efficient optical code-division multiplexing transmission system

A highly spectral-efficient transmission system based on optical code-division multiplexing (OCDM) technique is investigated. To meet the rapid increase in the demand of data bandwidth, spectral efficiency is becoming a key factor in optical transport systems. Several modulation formats along with the optical receiver design have been proposed to upgrade the spectral efficiency. OCDM is one of the promising techniques for this purpose. OCDM is the other class of multiplexing technique than optical time-division multiplexing and wavelength-division multiplexing (WDM). OCDM provides unique features such as asynchronous transmission, secure communication, soft capacity on demand, and high degree of scalability. In this paper, we apply OCDM technique to the highly spectral-efficient transmission system by quaternary phase-shift keying optical encoding/decoding along with ultrafast optical time-gating and optical hard thresholding. As a result, a transmission of 6.4 Tbit/s OCDM/WDM (4 OCDM/spl times/40 WDM/spl times/40 Gbit/s) using only C-band wavelength region is experimentally demonstrated with 1.6-bit/s/Hz spectral efficiency.     

微机保护动作过程可视化分析技术的实现

介绍了微机保护动作过程可视化分析技术的实现方案和分析软件的主要功能.着重讨论了数据的存储、记录格式和通信传输,以及对保护装置硬件的要求.数据记录采用一种分段记录的格式,在保证记录有效数据的前提下,大大减少了记录数据量,有利于数据的存储和通信传输.分析软件功能强大,除了对录波数据进行分析之外,还能动态再现保护动作逻辑流程.     

输电线故障录波及定位系统的研究

新型电力系统故障录波及定位系统是记录输电线路故障信息的智能自动化仪器，该仪器集工控机、GPS（全球卫星定位系统）、高速数据采集卡、DSP（数字信号处理器）于一体，利用虚拟设备驱动程序（Vxd)和多线程技术，提供Windows操作平台，具有全网同步高速大容量的数据采集、录波监控及定位功能。     

基于最小二乘法的线路录波数据同步及故障测距

高压输电线路两侧故障录波装置由于自身子时钟存在误差,导致二者采集到的录波数据在时间上不同步,利用该数据进行故障测距的结果精度较差,无法为排除故障提供便利。为了充分利用故障录波数据,需对两端录波数据进行同步处理。文章阐述了目前工程中采用的差流法、相位法和启动时刻对时法原理及步骤,对其各自的性能进行了对比分析,在此基础上提出了一种基于最小二乘法,利用线路参数实现两端录波数据同步的方法,并将其应用于故障测距。通过PSCAD仿真数据和实际故障录波数据的验证可知利用最小二乘法对故障录波数据进行同步后,故障测距误差降低至1%,大大提升了结果的可靠性和可信性。     

基于OPGW光传感输电线路雷击波形特点分析

光纤复合架空地线(OPGW)以其独特的优越性在电力系统智能状态监测领域得到了快速发展和应用,文章对OPGW光偏振态雷击故障定位方法中光纤传感雷击信号波形问题进行研究。首先利用ATP-EMTP软件建立输电线路模型仿真得到雷击OPGW时的电气数据,然后基于法拉第磁光效应原理将电信号转换为OPGW内部光纤中的光偏振态信号,此方法可用于仿真计算出雷击OPGW时光信号传播数据。实际输电线路上安装的OPGW雷击定位系统数据验证了仿真结果的准确性,结果表明OPGW光传感输电线路雷击波形受雷电流大小影响较大且不同于传统的电流行波雷击波形。     

基于圆柱体耦合结构的液漏检测 光纤传感器

针对现有侧耦合结构的液漏监测光纤传感器耦合结构损耗大、一致性低的问题,提出了一种圆柱体缺陷耦合结构的液漏传感器。通过Zemax软件进行光纤耦合仿真,对比分析圆柱、圆锥与半球体三种结构,在插入损耗相差较小的情况下,圆柱体耦合结构具有更高的耦合率。对聚合物光纤（POF）进行加工,得到插入损耗为0.31dB的圆柱体耦合结构。LED灯带作为扫描光源,对带有耦合结构的光纤进行检测能力验证,当耦合介质由空气变为水时,光功率强度变化可达32.8%以上。实验结果表明,圆柱体耦合结构与现有耦合结构相比损耗明显降低,所涉及的光纤传感器能够对液漏进行有效检测。     

High-capacity undersea long-haul systems

This paper reviews technologies and techniques that have been used in deployed long-haul wavelength division multiplexing (WDM) systems and emerging technologies that could be used for the next generation of cost-reduced systems. The overview of current generation technologies starts with a discussion of modulation formats, focusing on the superior properties of the chirped return to zero on-off shift keying (CRZ-OOK) modulation format. The use of 10-Gb/s CRZ-OOK modulation format together with advanced fiber types, more powerful forward error correction (FEC), and broadband erbium-doped fiber amplifiers resulted in the deployment of dense WDM systems with capacities per fiber in terabits per second range and trans-Pacific reach. Demand for the systems with large design capacity led to further development of broadband optical amplifiers. Laboratory demonstrations successfully expanded transmission into the full C-band and later in the C and L transmission bands. The current market conditions dictate the need for reducing the first cost of an installed system rather than reaching record capacity per fiber. Reducing first cost can be achieved by reducing the amount of optical amplifiers in the cable by utilizing an excess performance margin provided by available RZ-OOK technology. Further improvements would be possible if more powerful FEC and modulation formats with better receiver sensitivity are used. For example, the RZ differential phase-shift keying (RZ-DPSK) modulation format with 3-dB better receiver sensitivity and better nonlinear tolerance to large amounts of accumulated dispersion is a very promising technology. This paper will review long-haul transmission results using RZ-DPSK and will compare the transmission properties of RZ-DPSK signals versus RZ-OOK signals. Due to superior receiver sensitivity, the RZ-DPSK modulation format can be an enabling technology for 40-Gb/s per channel transoceanic transmission.