Design and applications of silica-based planar lightwave circuits

Planar lightwave circuits (PLCs) are waveguide devices that integrate fiber-matched optical waveguides on silicon or glass substrate to provide an efficient means of interaction for the guided-wave optical signals, PLCs provide various important and functional devices for optical wavelength-division multiplexing, time-division-multiplexing systems, and subscriber networks. This paper reviews the recent progress and future prospects of PLC technologies including arrayed-waveguide grating multiplexers, optical add-drop multiplexers and hybrid optoelectronics integration technologies     

CWDM Transmitter Module Based on Hybrid Integration

A simple concept for hybrid integration and packaging of III/V active devices in a multipurpose optical platform is introduced. The board could be used as a coarse wavelength-division multiplexing transmitter with four lasers or as a receiver with photodiodes, respectively. The assembly ensures ample heat dissipation, so the laser performance does not suffer after the packaging.     

Silica-based planar lightwave circuits: passive and thermallyactive devices

Silica-based planar lightwave circuits (PLCs) are playing key roles in both optical dense wavelength-division multiplexing networks and optical access networks. This paper provides an outline of PLC technology focusing on passive devices such as arrayed waveguide grating multiplexers     

Silica-based planar lightwave circuits

Silica-based planar lightwave circuits (PLC) provide various important devices for both optical wavelength-division-multiplexing networks and optical access network. This paper is an overview of recent progress in PLC technology including optical power splitters, arrayed-waveguide gratings, thermooptic switches, and hybrid integrated PLC's     

3-D photonic circuit technology

Vertically coupled, wafer-bonded III-V semiconductor waveguide devices provide a means to obtain more powerful, compact photonic integrated circuits and allow for the combination of different materials onto a single chip. Various switching, filtering, multiplexing, and beam splitting devices in the InP-InGaAsP and GaAs-AlGaAs systems for signals in the 1550-nm range have been realized. An investigation of optimal optical add-drop multiplexer waveguide layout shapes has been performed through integration of the coupled-mode Riccati equation, providing potential sidelobe levels of less than -32 dB and filter bandwidths over 20% narrower than those of previous devices. Effects of nonideal processing conditions on filter performance are analyzed as well.     

Silicon oxynitride planar waveguiding structures for application inoptical communication

The refractive index of silicon oxynitride (SiON), a widely used material for integrated optics devices, can be chosen in a wide range between 1.45-2.0. We describe how the consequent large design freedom can be exploited on the one hand for a “standard” polarization independent optical channel waveguide having a favorable tradeoff between efficient fiberchip coupling and small bend radii (compact devices) and on the other hand for special-purpose and hybrid components where the refractive index should be finely adjusted for obtaining the desired functionality. We illustrate the applicability of SiON by describing a few devices for optical filtering in a new architecture for wavelength multiplexing, modulation, polarization splitting and second-harmonic generation     

Integrated-optic versus microoptic devices for fiber-optictelecommunication systems: a comparison

We assess the relative merits and prospects of integrated-optics in comparison with microoptic and fiber-based techniques. Firstly, the market for fiber-optic components for telecommunications is analyzed. Secondly, the technological issues which make integrated optics quite different from integrated electronics will be discussed. Thirdly, a specific comparison between the potential of the competing optical technologies will be made for the polarization-diversity hybrid and the optical wavelength (de)multiplexer, two optical devices used in networks that are based on optical frequency division multiplexing (OFDM)     

Cyclic Short-Time Varying Channel Estimation in OFDM Power-Line Communication

In this paper, we consider an orthogonal frequency-division multiplexing (OFDM) communication system over a power-line channel (PLC) that exhibits cyclic short-time variations. In order to follow the cyclic channel variation, a blind estimation method is proposed. Simulations on an indoor PLC network show that the proposed estimation method is suited for following the short-time variation of the channel, achieving a better bit-error rate (BER) than a base pilot-aided method.     

Power modules for appliance motor control

The use of inverters in appliance applications is increasing rapidly. This paper describes hybrid power modules that utilize a unique injection-molded lead-frame design and provide the cost-effective integration of power devices, gate drive and protection for such applications     

A loosely synchronous-coded OFDM system for power-line communications in home networks

High-speed data communication is critical for home networks to support the increasing needs of online multimedia entertainment. Power-line communication (PLC) presents a 'no new wires' solution for home networks. However, power line is a troublesome and noisy platform for home networks. And the traditional approach with PLC is interference-limited and has a small bandwidth. In this paper we propose a new scheme of orthogonal frequency-division multiplexing (OFDM) to provide better noise-limited PLC networks. This schema is based on loosely synchronous (LS) codes with very nice correlations. Construction criteria of LS codes used in the proposed system are provided and discussed. The capacity properties and spectral efficiency of LS coded OFDM systems over PLC channels are also studied in this paper. We show that the proposed LS coded OFDM can efficiently achieve the diversity provided by power line channels. Such a schema can be employed in PLC to increase data throughput, system capacity and spectral efficiency in home networks.     

低压电力线载波通信的应用与发展

低压电力线载波通信以其覆盖范围广、连接方便、应用潜力巨大的显著特点,而被日益关注,成为近年来研究的热点。在介绍低压电力线载波通信特征的基础上,分析了正交频分复用和扩频技术在低压电力线载波通信中的应用,探讨了低压电力线载波通信在远程抄表和接入Internet的应用。     

对电力线上网技术的应用研究及分析

电力线上网（PLC）通过采用多载正交频分复用调制的关键技术，能够提供高速的数据传输速率，将整个家庭的家用电器与网络连为一体，推动家庭电器数字化的普及，很好解决了“最后一百米”的接入问题。随着PLC技术的发展，电力线上网将具有更加广阔的应用市场和发展前景。     

河南电力继电保护信号传输通道现状分析

介绍了河南省电力通信网络概况,对电力线载波、微波和光纤这3种主要传输继电保护信号的方式进行了比较,重点分析了光纤网络中继电保护通道64kbit/s、E1和光纤复用的特点。最后,对复用通道存在的安全问题进行了探讨,为今后在网络规划中对保护通道的要求提出了建议。     

基于正交频分复用的电力载波宽带远动通信系统

论述了基于正交频分复用（OFDM）的电力载波宽带远动通信系统,提出将OFDM调制技术运用于10kV配电网电力线载波通信中,可以达到1Mbps以上的数据通信速率,满足中压配电网宽带远动通信高可靠性需要。分析了基于OFDM的电力载波宽带远动通信系统关键技术,相比传统的电力线载波通信技术而言,它可以提供更高的频谱利用率、更快的通信速率、更好的抗信道衰落性能以及更高的可靠性。     

A Unified Approach to the Sizing and Control of Energy Storage Systems

Grid operation and planning challenges arising out of large-scale integration of renewable power can to a large extent be solved by the use of energy storage systems (ESSs). The type and size of storage to be used may be decided by the amount of fluctuating power the storage charges or discharges to attain its objective. Storage systems can be used as single devices or as hybrid systems where two or more devices complement the working of each other. The objective of this paper is to find an accurate power and energy sizing methodology for storage devices working in a single or hybrid arrangement such that the power fed to the grid from a wind turbine generator is regulated to a constant value. A strategy for sizing of a hybrid ESS is proposed by choosing the long-term storage to be a battery energy system and the short-term device to be a flywheel and using frequency analysis techniques. In the case of flywheel energy storage system, the inertia and the gain of an integral controller applied to an induction-machine-based flywheel are obtained. The simulations are done in MATLAB.     

低压电力线OFDM载波通信系统符号定时同步方法

正交频分复用(OFDM)技术用于低压电力线载波通信可以有效克服电力线弥散信道的多径、频率选择性衰落特性的影响.但OFDM系统对同步误差的影响相当敏感,准确的符号定时和频偏估计是实现OFDM系统的关键.文中采用改进的延迟相关符号定时同步方法实现了低压电力线OFDM载波通信系统的准确符号同步.对比分析了双滑动窗功率比值法、延迟相关算法、改进的延迟相关算法应用于实际低压电力线弥散通信环境中的效果,结果表明采用改进的延迟相关算法更稳定可靠,精度更高.实际低压电力线信道实验网络测试表明,改进的延迟相关算法可以更准确有效地进行OFDM系统符号定时,且符号定时同步不受频偏影响,具有很强的鲁棒性.     

城市路灯监控系统的分布式体系结构设计

提出一种基于分布式架构的体系结构,分析了部分设计决策在实际应用中对系统的建设、运行和维护产生的影响.结合路灯监控应用和嵌入式平台的特殊环境,在一些方面,系统地提出了特殊的设计和技术,如地理信息系统(GIS)的水平集成方式、ZjgBee与电力线通讯混合网络、多级流水并行协议栈、嵌入式远程调用的可扩展标识脚本、嵌入式的远程更新动态链接技术以及智能内存管理单元等.这些技术的综合运用为提高系统性能,改善系统维护性和控制系统成本发挥了重要的作用.     

基于电力线信道的正交频分复用仿真系统

根据电力线信道模型提出了一种新的基于正交频分复用(OFDM)技术的电力线通信仿真平台。在介绍OFDM基本原理以及给出电力线信道基本模型后，针对OFDM技术在实际电力通信过程中出现的问题，提出具体的解决实现方案，包括算法的选择以及参数的设定。还根据电力线通信给出了一种新的载波同步和符号同步方法。最后，对仿真系统参数以及仿真结果进行分析和说明。     

基于混沌跳频的电力线交织编码技术

可靠性是制约低压电力线载波通信广泛应用的一个重要因素。作为公用网络,低压配电网通信的安全性也日益受到关注。从提高通信可靠性和安全性出发,论述了正交频分复用（OFDM）技术和混沌跳频（CFH）技术在电力线通信上应用的优缺点,分析了2种技术结合的可行性,提出并设计一种适合高速电力线载波通信的CFH-OFDM系统。该系统将混沌跳频技术引入正交频分复用的编码中,提高了系统抗信道噪声的能力,并改进了通信系统的安全性。仿真实验表明,该方法可以提高系统通信的纠错能力,保证通信的可靠性,并为提高低压电力线载波通信系统的信息安全提供一种值得借鉴的方法。     

Optimized pulse source employing an externally injected gain-switched laser diode in conjunction with a nonlinearly chirped grating

In this paper, we demonstrate the generation of transform-limited short optical pulses, which display excellent spectral and temporal qualities by employing a novel technology, based on an externally injected gain-switched laser in conjunction with a nonlinearly chirped grating. Using this technique, 3.5-ps optical pulses exhibiting a time-bandwidth product (TBP) of 0.45 are generated, which are suitable for use in high-speed 80 Gb/s optical time-division multiplexing (OTDM) communications systems. The numerical integration of a set of rate equations using suitable parameters for the devices used in the experiments were carried out to further confirm the feasibility of the proposed method for developing an optimized pulse source for high-speed photonic systems.