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     

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     

Short-term project on microwave passive planar circuits: aneducational approach

The paper presents a short-term project on microwave planar circuits proposed to undergraduate students at Universite Catholique de Louvain, Belgium, in the frame of a basic course on microwave engineering. It helps the students to familiarize with all circuit aspects at microwaves and millimeter waves: they design, analyze, realize, and measure a planar passive component operating in the frequency range 0-40 GHz. Their attention is especially focused on microwave concepts: modeling a transmission line behavior and its limitations, spurious effects at high frequencies (radiation, coupling, and reactive behavior from higher order modes), influence of etching, mechanical tolerances, and wide-band behavior. The educational relevance of the project results from the opportunity given to the students to obtain in a very short period of time an actual component by combining up-to-date theoretical models, modern etching facilities, and measurement equipment, like in industry. Such an opportunity is rather unique and of prime interest for their possible future career in the growing area of microwave and millimeter wave communications     

Simulating circuits and devices

The successful engineering realization of high-frequency components and systems for these applications is heavily dependent on computer-aided design (CAD) in numerous respects. There are many different types and levels of modeling and simulation that may be involved, but the following discussion focuses on device modeling and circuit simulation, while also trying to place these within the wider high-frequency, computer-based design context, where possible. Furthermore, much of modern high-frequency design is driven by monolithic microwave integrated circuit (MMIC) technology and the greater levels of integration made possible using this technology. Accordingly, in this short overview of microwave device modeling and circuit simulation, we restrict our attention primarily to MMIC-based design.     

Variable group-delay dispersion equalizer using lattice-formprogrammable optical filter on planar lightwave circuit

The authors report, in detail, an integrated-optic variable group-delay dispersion equalizer based on a lattice-form programmable optical filter. The variable dispersion equalizer consists of an alternating cascade of symmetrical and asymmetrical Mach-Zehnder interferometers. An equalizer with nine symmetrical and eight asymmetrical interferometers is fabricated on a planar lightwave circuit and its dispersion varied step by step from -681 to +786 ps/nm in the operational frequency range of 16.3 GHz. The effectiveness of the equalizer is shown by compensating the dispersion of three different fibers with a single equalizer. The performance of the equalizer is also evaluated and examined by numerical investigations     

Parametric synthesis of passive filter-compensating devices

A method of optimal design for passive power filters based on performance optimization in the space of input impedance parameters is considered. The poles and the normalization coefficient of the filter operating impedance are variable parameters. A filter designed with the help of the proposed method satisfies requirements of reactive power compensation, harmonic filtering, and minimizing the amplification of minor harmonics. A design example illustrating the proposed approach is given.     

Finite difference time-domain analysis of planar microwave circuits

Contents The application of finite difference time domain analysis techniques to planar microwave integrated circuit design is discussed. It is shown that using this technique, three-dimensional discontinuity problems in planar microstrip and coplanar circuits can be analyzed in a full-wave approach.

---

Finite-Differenzen-Analyse von planaren Mikrowellen-schaltungen im Zeitbereich

Übersicht Es wird die Anwendung der Finiten-Differenzen-Analyse elektromagnetischer Felder im Zeitbereich auf den Entwurf integrierter Mikrowellenschaltungen diskutiert. Es wird gezeigt, daß durch Anwendung dieser Technik eine Lösung der Beschreibungsprobleme für dreidimensionale Schaltkreis-Diskontinuitäten in planarer Mikrostreifenleitungstechnik und in koplanarer Leitungstechnik unter Berücksichtigung der vollen Welleneigenschaften gefunden werden kann. Verschiedene Beispiele von Analysen planarer Mikrowellenbauelemente werden diskutiert und die Ergebnisse mit Messungen verglichen.

---

---

Dedicated to Prof. Dr.-Ing. Herbert Döring on the occasion of his 80th birthday     

Radiation performance of planar junctionless devices and junctionless SRAMs

The objective of this work is to analyze the radiation performance of the planar junctionless devices and junctionless device-based SRAMs. Bulk planar junctionless transistor (BPJLT) and silicon-on-insulator planar junctionless transistors (SOIPJLT) under heavy ions irradiation have been studied using TCAD simulations. 6T-SRAM cells built up of BPJLTs and SOIPJLTs have been investigated for their soft error performance. Even though the bipolar amplification of the SOIPJLT is more compared to BPJLT, the soft error performance of the SOIPJLT SRAM is better compared to BPJLT SRAM.     

Amorphous silicon-based guided-wave passive and active devices forsilicon integrated optoelectronics

Waveguides and interferometric light amplitude modulators for application at the 1.3- and 1.55-μm fiber communication wavelengths have been fabricated with thin-film hydrogenated amorphous silicon and its related alloys. The technique adopted for the thin-film growth is the plasma- enhanced chemical vapor deposition, which has been shown to give the lowest defect concentration in the film. Consequently the proposed waveguiding structures take advantage of the low optical absorption shown by a-Si:H at photon energies below the energy gap. In addition a good radiation confinement can be obtained thanks to the bandgap tailoring opportunity offered by this simple and inexpensive technology. In particular rib waveguides, based on a a-SiC:H/a-Si:H stack, have been realized on crystal silicon, showing low propagation losses. Recently, however, a new interest as low as 0.7 dB/cm. The same structure has been utilized for the fabrication of thermooptic Fabry-Perot modulators with switching times of 10 μs. Modulators based on the alternative waveguiding configuration ZnO/a-Si:H, giving comparable results, are also presented     

并联型无源与有源次同步振荡阻尼装置对比分析

提出了并联型FACTS装置抑制次同步振荡的无源阻尼与有源阻尼的概念。以静止无功补偿器和全控型换流器作为实现方法。采用复转矩系数法,分别推导了机端接入方式下,2种次同步振荡阻尼方法提供的阻尼系数和正阻尼条件,对比了影响二者提供正阻尼大小的相关因素。分析结果表明,无源阻尼的大小与阻尼装置接入点系统电压大小成正比,有源阻尼的大小则不受接入点电压大小的影响,而主要与其自身产生的次同步电压大小成正比。采用机端阻尼控制方式,分别对2种阻尼装置的控制器进行了设计。采用测试信号法,通过相位补偿,分别对阻尼装置提供的正阻尼进行了优化。时域仿真结果表明,对于短路故障引起的次同步振荡,在装置容量相同的情况下,有源阻尼方法较无源阻尼方法具有更强的阻尼能力。     

Transverse tranśmission theory for multilayer planar microwave circuits

Transverse transmission concepts in the Fourier transmission domain for multilayer planar transmission medium are presented. This complete transverse transmission theory (TTT) is found to be a superset of different Fourier-transform-based numerical techniques widely used in guided wave analysis, namely the modematching method and the spectral-domain approach. The features of the theory are: the expansion of field quantities in longitudinal section (LSE/LSM) modes, the concept of rotation of the transverse field vectors, and a comprehnsive algorithm using recursive matrix standard form. It is shown that the mode-matching method and spectral-domain approach are generally equivalent except for the last step of imposing the final boundary conditions, and can therefore be summarized in a unified theory within the framework of TTT. In addition, a new parameter, the polarization coefficient, has been introduced to describe the field polarization of the guided wave in a quantitative manner. It is believed that the present theory will help us to gain more insight into hybrid mode propagation in multilayer planar circuits.     

Applications of PSPICE simulation software to the study ofoptoelectronic integrated circuits and devices

Software models for Si and GaAs pin photodetectors are described, for use in the simulation of optoelectronic integrated circuits (OEICs). These preliminary models, which include the effects of dark current and lumped internal impedance, are completely integrable with PSPICE software, and may be used to study the operating characteristics of independent devices and cascaded components in complex OEICs. Parametric device dependence on applied bias, doping density, and wavelength of incident light are also established. The simulation of more advanced OEICs can be implemented with the subsequent modeling of other passive and active components, including waveguide modulators and light emitting sources. The use of PSPICE simulation software in the study of optoelectronic devices and circuits described should find wide application in upper division core or elective optical electronic courses and laboratories     

Silica-based functional fibers with enhanced nonlinearity and theirapplications

Silica-based optical fibers are now being used in various applications which utilize nonlinear effects in fiber. In addition to enhancing nonlinearity of optical fibers, tailoring chromatic dispersion is one of the important design issues in such applications. Highly nonlinear dispersion-shifted fibers have been developed, and a very compact wavelength converter module has been demonstrated by using the fiber. Dispersion-flattened and dispersion-decreasing fibers have also been proved to be highly effective for supercontinuum generation     

被动式直接硼氢化物燃料电池堆的设计与测试

设计了一种无膜型被动式直接硼氢化物燃料电池(DBFC)堆,对由4个电池单元(电极面积为2 cm2)通过后空翻式串联而成的电池堆研究表明:其开路电位达3.6 V,最大功率达400 mW;采用KBH4为燃料时DBFC的性能优于NaBH4;放电稳定性主要受硼氢化钾水解产生的H2气泡影响较大。     

Design of planar integrated passive module for zero-voltage-switched asymmetrical half-bridge PWM converter

Integrated inductor-inductor-capacitor-transformer (L-L-C-T ) technology has been the subject of intensive research over the last few years. Its application to resonant power electronics converters has been reported in many previous publications. This paper presents the application of a planar L-L-C-T module to the integration of passive module for a zero-voltage-switched (ZVS) asymmetrical half-bridge pulsewidth-modulation converter (AHBC) for application in a distributed power system. Two output transformers, two current-doubler inductors, the ZVS resonant inductor, and the transformer DC decoupling capacitor are integrated into a single module. The design procedure is discussed and some special considerations of the L-L-C-T module in nonresonant applications are addressed. A 1 kW 300 V-400 V input 48 V output AHBC employing the L-L-C-T module is constructed. A comparison of the AHBC using the integrated passive module and the same circuit using discrete components is given.     

Positive‐real property of passive fractional circuits in W‐domain

Fractional circuits have attracted extensive attention of scholars and researchers for their superior performance and potential applications. Fractional circuits constitute a new challenge for the analysis and synthesis methods of traditional circuits theory. Passivity is the fundamental property of traditional circuits (integer order electric circuits). As is known to all, passivity is equivalent to positive realness in traditional linear circuits. However, this equivalence is broken down by introducing fractional elements into electrical networks in s‐domain. To address this issue, on the basis of s‐W transformation, we study the passive criteria of fractional circuits with rational order elements in this paper. Definitions of positive‐real (matrix) function in W‐domain are given, and the equivalence conditions of positive realness are derived. In addition, a conclusion is proposed in which the immittance (matrix) function of passive fractional circuits with rational order elements is positive real in W‐domain. The applications of passive criteria in circuit synthesis are shown.     

Efficient analysis of planar microwave circuits with mixed‐order prism vector finite macroelements

This paper introduces a new concept of a mixed‐order prism macroelement, suitable for an efficient analysis of three‐dimensional planar microwave circuits, using two‐dimensional meshes and preprocessors. The mixed‐order concept used here implies arbitrary orders of variation in different directions and differs essentially from the well‐known mixed‐order approximation that is an integral part of every Whitney element. It is the existence of a related systematic theory of higher‐order vector finite elements, previously documented, that facilitates the introduction of such a concept. The second‐ and third‐order elements, derived by this approach, are successfully applied in the analysis of planar microwave circuits, rendering the application of finite element method in such problems still a favorable option. Copyright © 2008 John Wiley & Sons, Ltd.     

Overview of on-chip electrostatic discharge protection design with SCR-based devices in CMOS integrated circuits

An overview on the electrostatic discharge (ESD) protection circuits by using the silicon controlled rectifier (SCR)-based devices in CMOS ICs is presented. The history and evolution of SCR device used for on-chip ESD protection is introduced. Moreover, two practical problems (higher switching voltage and transient-induced latchup issue) limiting the use of SCR-based devices in on-chip ESD protection are reported. Some modified device structures and trigger-assist circuit techniques to reduce the switching voltage of SCR-based devices are discussed. The solutions to overcome latchup issue in the SCR-based devices are also discussed to safely apply the SCR-based devices for on-chip ESD protection in CMOS IC products.