多路FM—SCM光波系统研制

介绍我们研制的多路ＦＭ－ＳＣＭ（调频副载波复用）光波系统及其性能，讨论了ＳＣＭ光波系统的噪声。该系统主要可用于多路ＣＡＴＶ光纤传输。采用Ｆ－Ｐ腔ＬＤ和ＰＩＮ－ＦＥＴ接收组件，通过系统优化，实现了接收端输出电视图象信号ＳＮＲ〉５５ｄＢ。     

高副载波复用光纤CATV系统的优化设计

高副载波复用（ＳＭＣＭ）ＡＭ－ＶＳＢ ＣＡＴＶ系统在国内正日渐引起人们的关注。本文提出了采用掺饵光纤放大器（ＥＤＦＡ）和线性化外调制器在系统中进行优化,以实现高副载波复用。并首次采用定量的无约束数值优化法,即单纯形法,对全系统中一些关键参数进行优化,从而为ＭＳＣＭ ＡＭ－ＶＳＢ ＣＡＴＶ系统的优化提供了一种有实际意义的通用方法。     

SMS－600W

ＳＭＳ－６００ＷＳＭＳ－６００Ｗ宽带插分多路夏用器（以下简称ＳＭＳ－６００Ｗ）是一符合ＣＣＩＴＴＥＴＳＩ标准的ＯＬＴＭ接入系统．它与ＳＭＳ－１５０相似，现已开发完成，可用以替代常规的用于同步网中的Ｎ６０００系列数字ＭＵＸ或ＯＬＴＭ。该系统的主要特点是...     

30路FM－TV光纤CATV传输系统

本文介绍一个设计研制的能传输３０路ＦＭ－ＴＶ光纤系统。系统的频率范围是１～２．５ＧＨ２。对光纤键路的光发射机设计作了详细的论述；系统的信道间隔设计成非等间隔的频率配置，减少了落入信道的二阶和三阶失真产物。实际测试系统的ＣＮＲ＞１８ｄＢ，ＣＳＯ、ＣＴＢ优于５０ｄＢｃ，传输距离＞３０ｋｍ。系统可以用于ＣＡＴＶ的干线或分配传输。     

一种新的用于高速波分复用系统的色散补偿方案

本文提出了一种用于高速多路波分复用（ＷＤＭ）陆上级联掺铒光纤放大器（ＥＤＦＡ）光纤通信系统的色散补偿方案，其特点是：利用特殊设计的色散位移光纤ＳＤＤＳＦ（零色散波长λ０≈１．６μｍ，色散斜率Ｓ＿０＝０．０５ｐｓ／ｋｍ／ｎｍ２），在１５５０ｎｍ处产生－２～－４ｐｓ／ｋｍ／ｎｍ的色散，以避免ＩＴＵ－ＴＧ．６５３色散位移光纤在多路复用时的四波混频（ＦＷＭ）效应；并利用ＩＴＵ－ＴＧ．６５２标准单模光纤（非色散位移光纤ＮＤＳＦ）在１５３０～１５７０ｎｍ（ＥＤＦＡ工作带宽）范围内，有效地补偿ＳＤＤＳＦ所引入的负色散。此方案可使单路数据率高于１０Ｇｂ／ｓ的波分复用系统，经１０００ｋｍ传输后因色散引入的眼图恶化量仍＜１ｄＢ。     

AM—VSB光纤1310nm波段750MHz CATV传输系统

对ＡＭ－ＶＳＢ光纤７５０ＭＨｚ ＣＡＴＶ系统的非线性补偿技术以及ＤＦＢ激光器的ＡＰＣ和ＡＴＣ电路进行了讨论和设计。给出了研制的ＤＦＢ光发射机及接收机的特性及实测结果。对光发射机的关键技术即预失真校正技术进行了论述,给出了研制的预失真电路的实测结果。在６０路ＰＡＬ制信号同时传输条件下,ＣＳＯ改善２～４ｄＢ,ＣＴＢ改善５～７ｄＢｃ。     

一种自外差－相干光纤系统与PIN－FET混频检测

一种自外差－相干光纤系统与ＰＩＮ－ＦＥＴ混频检测汪开源，徐伟弘，唐洁影（东南大学电子工程系，２１００１８）ＡＳｅｌｆ－Ｈｅｔｅｒｏｄｙｎｅ／ＣｏｈｅｒｅｎｔＦｉｂｅｒＳｙｓｔｅｍａｎｄＰＩＮ－ＦＥＴＭｉｘｉｎｇＦｒｅｑｕｅｎｃｙＭｅａｓｕｒｅｍｅｎｔ...     

低通滤波器结构的改进分析及模拟

在高频域，ＭＯＳＦＥＴ的分布参数对全集成ＭＯＳＦＥＴ－Ｃ滤波器的特性有很大影响，本文应用ＳＰＩＣＥ（Ⅱ）通用模拟电路程序，采用非理想运算放大器单极点电路模型，考虑到ＭＯＳＦＥＴ的寄生电容，对一个六阶切比雪夫低通滤波器全ＭＯＳＦＥＴ－Ｃ平衡结构应用传输线模型进行了仿真分析。     

一种基于DMT技术的HFC反向信道传输方案

详细阐述了用于ＨＦＣ（光纤混合同轴电缆）网络上行信道数据传输的ＳＤＭＴ（同步多载波调制）系统的原理,分析了其性能。与采用单载波系统进行比较,得到的结论是：ＳＤＭＴ具有更大的优越性,它是用于ＨＦＣ反向信道传输的一个较先进的解决方案。     

FM-SCM光纤多路电视传输系统

本文简要叙述ＳＣＭ系统的工作原理与特点，系统的载噪比和系统的信噪比，还对ＦＭ－ＳＣＭ系统的实施方案进行了讨论。     

光纤SCM通信系统容量的极限

本文以光纤CATV传输系统为例.研究分析了SCM传输技术中容量的限制。导出了各种副载波调制型式(数字信号的PSK、FSK、ASK,模拟信号的FM、AM和AM-VSB)的容量极限值与系统中主要器件技术参数间的关系。     

Subcarrier multiplexed lightwave systems for broad-banddistribution

Microwave subcarrier multiplexing (SCM) is an important approach to the design of lightwave systems for broadband distribution. Recent progress in the design and performance of both analog and digital multichannel SCM systems is reviewed. The application of broadband SCM systems to both passive and optically amplified distribution networks is discussed. The discussion covers the general features of SCM systems; the electrooptic components that have been used in the system experiments described here, including laser intensity noise and noise due to intermodulation products; the carrier-to-noise ratio requirements; some multichannel FM systems experiments; and a 20-channel digital systems experiment; and a hybrid system carrying 60 FM SCM channels plus a 100-Mb/s baseband digital channel. Several approaches to broadband subscriber distribution networks are analyzed     

Subcarrier multiplexed lightwave system design considerations forsubscriber loop applications

Design considerations for subscriber multiplexed (SCM) systems distributing multichannel analog/digital signals are reviewed. In particular, video distribution schemes based on lightwave transmission technologies are discussed. The two most important system design considerations in an SCM system are the control of intensity noise and nonlinear distortions. Intensity noise characteristics and degradation caused by optical reflections are discussed. Laser and detector linearity requirements are reviewed. System signal-to-noise ratio analysis is performed. Design considerations for receivers for SCM systems are reviewed, and various system applications are examined     

光栅多通道光学双稳性系统的理论分析

本文提出了一种由两个平行放置的正弦位相光栅构成的混合型多通道光学双稳性系统。理论上推导出了描述此系统的调制性和双稳性的数学模型。基于此模型,对不同参数情况下,此系统的调制性和双稳性进行了数字模拟。最后,对数字模拟结果进行了分析和总结.此系统有可能应用于光通信和光信息处理等领域。     

光纤CATV信号传输对激光器要求的分析

激光器是多频道光纤ＣＡＴＶ系统中提高传输信号质量的关键器件,特别是在受色散和非线性影响的基于Ｇ．６５２光纤的１５５０ｎｍＶＳＢ－ＡＭ系统中。文章从激光器的本征特性和光纤的传输特性的角度讨论了系统对激光器性能的特殊要求,提出能够满足系统要求的激光器的典型性能指标,并介绍了几种适用于光纤ＣＡＴＶ的新型激光器及其发展。     

光纤接入网的用户线交叉连接系统

最近问世的用户线交叉连接系统（ＬＸＭ）属于高速数字式多路交叉连接系统，其作用是充当光纤接入网的窄带业务平台，使其收容的各种用户可以接通交换系统，这些专供光纤接入网使用的ＬＸＭ有利于ＦＴＴＨ（光纤到户）目标的顺利推行，本文对ＬＸＭ的用途及其技术概念做了必要的轮廓性解说。     

A 20-channel optical communication system using subcarriermultiplexing for the transmission of digital video signals

Microwave subcarriers have been used to demonstrate an optical communication system suitable for the distribution of digital video channels. The design, performance, and optical link requirements are discussed for a 2-Gb/s subcarrier-multiplexed (SCM) system with 20 microwave subcarriers modulated at 100 Mb/s and using a frequency-shift-keyed format. The system uses the 2-6-GHz bandwidth and represents the first example of an SCM system using more than one octave of bandwidth. The bit error rate was measured for all 20 channels; results for five typical channels are shown and discussed. The performance results show that a digital SCM approach is attractive in an optical link for a multichannel wide bandwidth video distribution system made from standard microwave components     

Subcarrier multiplexed coherent lightwave systems for videodistribution

The application of subcarrier multiplexing techniques to coherent lightwave systems designed for video transmission is described. The theory of the intrinsic receiver sensitivity of multichannel coherent SCM (subcarrier multiplexing) systems is presented. Specific implementations of SCM coherent systems transmitting 60 FM video channels and 20 100 Mb/s FSK (frequency shift keying) channels are described. It is shown that a simple phase noise canceling circuit can be implemented, which allows these systems to be built with wide-linewidth DFB (distributed feedback) lasers. Several applications of multichannel coherent SCM systems to video distribution networks are proposed     

Coherence-Multiplexed Optical RF Feeder Networks

An optical RF feeding system for wireless access is proposed, in which the radio access points are distinguished by means of coherence multiplexing (CM). CM is a rather unknown and potentially inexpensive optical code division multiple access technique, which is particularly suitable for relatively short-range applications with moderate transmission bandwidth requirements. Subcarrier multiplexing (SCM) can possibly be used on top of CM, either as single-channel or multichannel SCM. The performances of the resulting distribution networks are analyzed, incorporating the effect of chromatic dispersion, optical beat noise, shot noise, thermal noise, and-in the case of multichannel SCM-intermodulation distortion. The results of the analyses are illustrated by using numerical examples, based on the IEEE 802.11b standard for wireless LAN.     

10-Gb/s Transmission on Single-Wavelength Multichannel SCM-Based FDDI-Grade MMF Links at Lengths Over 300 m: A Statistical Investigation

We propose and comprehensively investigate a subcarrier-multiplexing (SCM) system based on 62.5-mum-core-diameter multimode fiber (MMF) using a single wavelength to achieve 10-Gb/s transmission over link lengths beyond 300 m, using 1.3-mum-wavelength lasers with radial offset launch into MMF links. The system utilizes multichannel SCM transmission using quadrature-phase-shift-keyed modulation in combining baseband transmission with three passband SCM channels at the carrier frequencies of 3.75, 6.25, and 8.75 GHz while incorporating a maximum laser modulation bandwidth of 10 GHz to ensure system compliance with the limits of current uncooled laser devices. A statistical investigation of the system highlights its capability to achieve an acceptable yield over worst-case MMF links of length 600 m. We also investigate the improvement in system performance granted by allowing a controlled overlap of frequency spectra of the passband SCM channels. In addition, we test the accuracy of the previously proposed usable average slope criterion of less than 4 dB/GHz, which is needed to achieve low-penalty transmission with eye-closure penalties <3 dB.