Circular groove guide for short millimeter and submillimeter waves

A new type of groove guide, circular groove guide, has been designed for use as a low losses, high power handling, low dispersion and single mode transmission medium in the short millimetric and submillimetric waves ranges. The characteristic equations of TE modes and TM modes have been developed and the propagation characteristics of the fundamental mode have been discussed. Experimental measurements are in good agreement with theoretical results     

Analysis of a dispersionfree guide for elastic waves

The properties of the lowest flexural mode of a wedge-shaped elastic waveguide are discussed. It is shown that this mode can be used as a dispersionfree topographic guide for acoustic surface waves. Curves completely characterising the guided mode for any value of the top angle are presented.     

Fence guide for millimeter waves

A new waveguide, called "fence guide," for millimeter-wave circuitry on a dielectric substrate is described. The structure of the guide, the field distribution, and its characteristics are considered.     

Penalty-free dispersion-managed soliton transmission over a 100-km low-loss PCF

A long photonic-crystal fiber (PCF) with a low loss was successfully fabricated by first preparing a large pure silica glass preform. The fiber is 100 km long and has a low loss of 0.3 dB/km at 1550 nm. The fiber has a Rayleigh scattering coefficient of 0.85 dB/(km/spl middot//spl mu/m/sup 4/), which is the lowest value ever reported in a PCF. Using this fiber, the first penalty-free dispersion-managed soliton transmission at 10 Gb/s was achieved in a PCF.     

Ultrawide-band single-mode transmission performance in a low-loss photonic crystal fiber

We describe the ultrawide-band single-mode transmission performance of a photonic crystal fiber (PCF) in the 850 to 1550 nm wavelength range. We confirmed that the fabricated PCF achieves a single-mode operation over the 850 to 1550 nm wavelength range by measuring the mode-field diameter (MFD) and modal delay characteristics. The 10-Gb/s-based wavelength-division multiplexing (WDM) signals with a total capacity of 190 Gb/s were successfully transmitted over a 5.2-km low-loss PCF utilizing the 850, 1310, and 1550 nm regions simultaneously. Our experimental results show that an endlessly single-mode PCF provides an ultrawide-band of more than 160 THz for future optical communication systems.     

高速传输系统用低损耗单模光纤的研究

介绍了国际上低损耗单模光纤的研究进展,从理论上分析了低损耗单模光纤实现的技术途径。通过对石英玻璃物理特性的研究,探索出石英玻璃光纤的退火工艺,以降低光纤的内应力从而降低光纤的衰减。采用自主知识产权的专利技术制造的光纤在1 310、1 550和1 625nm波长的衰减典型值分别为0.320、0.182和0.195dB/km。该光纤的技术指标优于ITU-T国际标准和GB/T规定的光纤指标值。     

New glass system for low-loss optical waveguides

Optical fibres have been made by the vapour deposition of P2O5-GeO2-SiO2 glass onto the inside surface of Corning Code 7913 glass tubes. These graded-index core waveguides exhibit low attenuations, i.e. 4.0 dB/km at 0.82?m.     

Properties of solitary waves as observed on a nonlinear dispersive transmission line

Several properties of solitary waves that were measured on an easily constructed transmission line of very modest size (50 sections ∼1-m length) are described. Among the properties observed are their generation by a pulse or a sine wave, the recurrence phenomena, and the collision of two solitary waves.     

应用于甚短距离光传输系统的并行帧对齐电路

简要介绍甚短距离光传输系统,分析各种帧对齐电路的性能,提出一种针对同步数字体系(SDH)高速数据的全新的基于二分查找的并行帧对齐电路。选用Altera公司Stratix EP1S25F780C5现场可编程器件芯片下载验证。仿真和测试表明,速度和芯片面积均较以往方法有较大提高。     

基于STM-64的甚短距离并行光传输系统

研究了STM-64数据帧的转换映射技术,利用垂直腔面发射激光器（VCSEL）列阵光源和PIN列阵探测器成功研制出10Gb／s的甚短距离12信道SDH并行光传输系统,该系统结构紧凑,具有检错和纠错功能。跟传统的10Gb/s串行光传输系统相比,本系统降低了对单路器件传输性能的要求。经SDH传输测试仪测试,系统能实现无误传输。     

基于STM-64的甚短距离并行光传输系统

研究了STM-64数据帧的转换映射技术,利用垂直腔面发射激光器(VCSEL)列阵光源和PIN列阵探测器成功研制出10 Gb/s的甚短距离12信道SDH并行光传输系统,该系统结构紧凑,具有检错和纠错功能.跟传统的10 Gb/s串行光传输系统相比,本系统降低了对单路器件传输性能的要求.经SDH传输测试仪测试,系统能实现无误传输.     

Tolerant low-loss three-lens coupling system for 1.48-μmunstable-cavity lasers

A 1.48-μm unstable-cavity laser is coupled into single-mode fiber using three microlenses. Reproducible coupling of very high power is demonstrated with different types of lenses (plano-convex or biconvex, with different apertures). Over 550 mW in single-mode fiber (SMF) were reproducibly reached; to our knowledge, it is the highest power coupled into an SMF from a single semiconductor laser at this wavelength. Tolerance measurements on all of the coupling elements of a three-lens system are reported for the first time; an unexpected very large tolerance an the axial displacement of the second lens was measured. Results and interpretation with the aid of Gaussian and aberration simulations are also presented     

Study of a new leaky-wave antenna for millimeter waves based on the V-groove guide

Journal of Infrared, Millimeter, and Terahertz Waves - In this paper a new type of leaky-wave antenna for millimeter waves using an asymmetric strip in the V-groove guide is presented. The...     

Reflection and transmission coefficients for backward waves on a corrugated YIG film

The reflection and transmission coefficients for the backward magnetic waves on a YIG film with periodic surface corrugations are systematically deduced from the solution of the full magnetostatic boundary-value problem. The phenomenological boundary condition for the slowly varying amplitude in the coupled mode equations is also obtained.     

Iterative symbol timing recovery for short burst transmission schemes

This paper presents a novel iterative symbol timing recovery (STR) scheme for short burst transmission formats, a paradigm commonly found in modern wireless systems, like, for instance, time division multiple access (TDMA) schemes and future wireless packet data networks. Both data-aided (DA) and decision-directed (DD) solutions are considered and performance is pursued by means of an iterative burst-by-burst scheme which exploits the Farrow structure for the polynomial interpolation filter. The convergence of the algorithm is discussed according to the expectation maximization (EM) framework. Performance is evaluated by simulating 4-QAM and 16-QAM transceivers and simulations results are compared under different modulation orders and channel conditions, for both the decision-directed and data-aided cases.     

Leaky NRD guide as a feeder for microwave planar antennas

Although leaky wave antennas have been studied extensively in the literature, their practical use is still limited. This work proposes a novel and unique application of leaky NRD guides as feeding systems for microwave planar antennas and shows their substantial possibilities of practical use. At first a new leaky waveguide is introduced based on a periodic array of grooves on the upper side of the dielectric strip in the NRD guide. Then, leaky waves issuing from this configuration are used to feed a slot array cut on the upper metal plate of the NRD guide. Design examples of linearly and circularly polarized planar antennas were constructed, and their characteristics were measured at 23 GHz. The obtained results show the validity for this application of the leaky waveguide     

Multiplexing system for Walsh waves

A sequency-division multiplexing system is described that operates on multilevel data signals, where the output carrier does not contain more levels than the input. The system also possesses an efficient tradeoff between error correction and the number of channels in use. All operations are done in the residue number system, where the ideal p is any odd number. The system is particularly suited for data coded in is-complement fashion, and results for a 16-channel system are shown.     

40Gb/S甚短距离光传输系统的去斜移设计(本期优秀论文)

实现了串/并转换成帧器接口(SFI-5)的去斜移功能.该设计主要由去斜移通道的帧对齐模块和数据通道去斜移模块组成,其中的关键电路由窗口比较器与滑动窗口生成器配合工作实现.16个数据通道去斜移电路轮流工作,共用一个窗口比较器,提高了电路的工作速度,节省了资源.系统测试表明,该电路可纠正±160比特范围内的通道间斜移,可应用于40Gb/s甚短距离传输的VSR5系统.     

基于短包通信的NOMA下行链路安全传输

面向物联网业务中的低时延需求,将短包通信(SPC)和非正交多址接入(NOMA)技术相结合,针对存在窃听者的情况研究多用户NOMA系统中的安全传输问题.以最大化弱用户的安全吞吐量为目标,考虑用户译码错误概率约束、总功率约束和功率分配约束,提出了一种低复杂度的功率分配方案实现系统安全传输.为解决复杂的目标函数和不可靠的串行...