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。     

色散补偿光纤应用技术的探讨

在分析色散补偿光纤（ＤＣＦ）应用原理的基础上，对ＤＣＦ特性的评价，ＤＣＦ和常规单模光纤连接损耗的降低，ＤＣＦ和掺饵光纤放大器（ＥＤＦＡ）与常规单模光纤线路的连接方式以及色散补偿传输系统中继距离的估算等应用技术进行了探讨，并提出了一些新的看法和建议。     

光纤色散对WDM系统性能的限制

波分复用（ＷＤＭ）技术是增大光纤传输容量的方法，但是在高速率、长距离ＷＤＭ系统中传输性能受到限制。除了多级光纤放大器（ＥＤＦＡ）使带宽减小，噪声增大，光纤的材料色散也是对ＷＤＭ系统影响的重要因素。本文主要分析光纤色散以及有初始啁啾的脉冲、激光器的相位调制噪声、有非线性效应时光纤色散对ＷＤＭ系统传输容量的影响。     

采用啁啾光栅的色散管理孤子传输

我们采用啁啾光纤光栅（ＣＦＢＧ）补偿１．３μｍＳＭ光纤传输线路的色散以后,成功地以１０Ｇｂｉｔ／ｓ速率进行了３,０００ｋｍ光孤子转输。实验中一个中继间隔由５２ｋｍ左右的１．３μｍＳＭＦ构成,经ＥＤＦＡ放大后采用ＣＦＢＧ进行色散补偿。     

朗讯科技的先进光通信技术

３．２８Ｔ ＤＷＤＭ试验系统 在用２０００年初在美国召开的世界光纤通信会议ＯＦＣ’２０００上,朗讯科技的３．２８Ｔｂ／ｓ ＤＷＤＭ试验系统是所有参会公司系统中容量最大的系统。其特点如下： 系统单波长速率为４０Ｇｂｉｔ／ｓ,共８２个波长,光滤波器波长间隔为１００ＧＨｚ。 系统工作于Ｃ和Ｌ两个波段,分别容纳４０和４２个波长通道。 系统传输距离３００公里,采用真波光纤,中间放大（Ｅ／Ｒ—ＯＡ）跨距１００公里。 光纤线路的色散补偿要分别对Ｌ、Ｃ波段补偿ＤＣＦ、ＨＳ—ＤＣＦ,分别为补偿光纤和高斜率补偿光纤。 系统…     

色散补偿光纤传统设计方案及相关算法的改进

随着光纤传输速率的不断提高,色散问题已成为光纤传输的重要制约因素,在未来的高速光传输网中,色散补偿光纤（ＤＣＦ）将得到广泛应用。文章对ＤＣＦ的传统设计方案及其有关算法作了改进,具有较高的实用价值。     

低衰减色散补偿光纤及其应用

本文介绍了用具有大的正常色散单模光纤作色散补偿光纤来抵消１．３μｍ零色散波长传输光纤的反常色散的设计原理。用ＶＡＤ法制作了Δ范围从１．６－３．５ 种ＣＤＦ，并检验了其性能。获得了最大Δ为３．５％的ＤＣＦ，其在１．５５μｍ波长处的最大色数为－１４０ｐｓ／（ｎｍ．ｋｍ）。随着Δ的增大，瑞利散射和缺陷衰减增加，致使传输衰减也增大。     

EDFA在模拟CATV中的应用及其对系统性能的影响

阐述掺饵光纤放大器（ＥＤＦＡ）的工作原理及其在ＣＡＴＶ系统中的应用,并着重讨论了ＥＤＦＡ对由ＥＤＦＡ＋ＤＷＤＭ组成的ＣＡＴＶ多波长模拟系统性能的影响及其解决措施。     

AM-CATV光纤传输系统中EDFA非线性失真的补偿

分析计算了掺铒光纤放大器（ＥＤＦＡ）在ＡＭ－ＣＡＴＶ光纤传输系统中引入的非线性失真，在总结了两种补偿方法的同时，提出了一种新的补偿方法——光补偿，计算机模拟和实验结果表明，它对ＥＤＦＡ的非线性失真有一定的改善。最后对这三种补偿方法进行了简单的比较     

Coupler WDM智能制造系统投入商用

Ｃｏｕｐｌｅｒ（光分路器）和ＷＤＭ（光波分复用器）智能制造系统目前在上海交大问世,并于上海嘉慧光电子技术有限公司（ｈｔｔｐ／／ｗｗｗ．ｊｏｉｎｗｉｔ．ｃｏｍ．ｃｎ）投入批量生产。ＷＤＭ是光纤通信网络中的核心器件,是ＩＰｏｖｅｒＷＤＭ的基础。ＥＤＦＡ＋ＷＤＭ是光网扩容最经济有效的方案,在发达国家已得到广泛应用。Ｃｏｕｐｌｅｒ（光分路耦合器）则在ＳＤＨ＋ＰＯＮ、ＡＴＭ＋ＰＯＮ及光纤ＣＡＴＶ的ＨＦＣ网中发挥重要作用。嘉慧公司ＦＢＴ系统是以熔融拉锥方式制造全光纤器件,效率高,成本低,据悉为国内最先推出的…     

波分复用系统中四波混频引入光信噪比的恶化及其抑制

本文对陆上级联接掺铒光纤放大器（ＥＤＰＡ）波分复用光纤通信系统中国波混频所造成的各个光信道光信噪比的恶化提出了一套计算方法，并结合常规单模光纤及一种特殊设计的色散位移光纤进行了分析计算。结果表明：在四波混频所引入的光信噪比恶化中，因新生频率分量导致的噪声增加一般远大于光信号功率的减弱。不等信道间隔划分能有效地避免四波混频的影响，而光滤波器的带宽应在允许范围内尽量压窄。对采用色散补偿技术的级联ＥＤＦＡ波分复用系统，在同一光中继段内，使常规单模光纤置于特殊设计的色散位移光纤之前，能进一步减少四波混频带来的光信噪比的恶化。     

Design of Dispersion Compensation and Nonlinear Distortion Self-compensation in Co-network Transmission Systems

Dispersion and nonlinear distortion have an effect on transmission performances of optical fiber transimission systems,The schemes of dispersion compensation and nonlinear distortion self-compensation in telecom-CATV co-network transmission systems are reported,followed by investigation on (1) the impact of dispersion compensation fiber (DCF) on fiber nonlinear effects with a cascade of erbium-doped fiber amplifiers (EDFAs) and different dispersion compensation schemes,(2) the impact of the complex on the total nonlinear distortion induced by EDFA gain tilt and the light source.As a result,dispersion compensation optimal scheme and EDFA negative gain tilt are suggested as a solution to dispersion compensation optimal scheme and EDFA negative gain tilt are suggested as a solution to dispersion compensation and the nonlinear distortion self-compensation.     

基于OOC的WDM+OCDMA系统性能研究

基于光正交码,研究了WDM+OCDMA系统的性能。采用4个波长信道和3个码字的光正交码OOC(37,4,1),对12个用户的WDMA+OCDMA进行了系统仿真,用户数据速率为1Gbit/s,单模光纤长为50km,色散补偿光纤长为5km。如需增加WDMA+OCDMA的用户数,可以通过增加波长信道数或码字容量来实现。分析了色散效应对WDMA+OCDMA系统性能的影响,研究了用户之间相对延时对多址干扰和系统性能的影响。     

Design Considerations for Transmission Systems in Optical Metropolitan Networks

Wavelength division multiplexing (WDM) has become a key technology in optical long-haul communications and wide area networks. Recently, interest in introducing WDM into metropolitan networks has increased. We look at some issues pertinent to the design of WDM transmission systems deploying optical add/drop multiplexers in these networks. In particular, we investigate the interaction of node-induced crosstalk with fiber nonlinearities in metropolitan ring networks. Two transmission systems are considered; namely a system of nonzero dispersion shifted fiber operating in the anomalous dispersion regime and another one of single mode fiber with post dispersion compensation. Data rate is assumed to be 10 Gb/s per wavelength. The dependence of the crosstalk/nonlinearity interaction and its system penalty on the frequency difference between signal and crosstalk carriers, input signal power, extinction ratio, number of nodes, and physical span of the network is examined in detail. It is shown that node-induced crosstalk can interact with fiber nonlinearities and introduce limitations on transmission performance. This interaction should therefore be taken into consideration in designing regional metropolitan networks.     

偏振模色散仿真器特性研究

光纤通信线路的偏振模色散已成为高速、长距离光纤通信系统发展的主要障碍之一 ,其特性、测量以及补偿方法的研究成为目前光纤通信研究热点之一。偏振模色散仿真器 ,用于仿真传输链路的偏振模色散特性 ,不仅可用于偏振模色散补偿器 ,也可用于高速长距离光纤通信系统的规划设计等。本文分析了光纤偏振模色散仿真器的研究现状 ,归纳总结了现有偏振模色散仿真器的设计原理和结构特征 ,并用蒙特卡罗法对常用的偏振模色散仿真器的特性进行了数值模拟     

1.6 Tbit/s(40×40 Gbit/s)光通信传输系统

在国家自然科学基金网(NSFCNet)上已实现由400 km×10 Gbit/s传输链路直接升级的一路400 km×40 Gbit/s光传输实验的基础上,采用自行研制的40×40 Gbit/s载波抑制归零(CS-RZ)码多波长光发送源,进行了160 km的1.6 Tbit/s(40×40 Gbit/s)波分复用(WDM)光传输实验。实验结果表明,对于常规中短距离10 Gbit/s传输链路可以直接升级至40 Gbit/s。但是由于40 Gbit/s传输系统的色散容限小于60 ps/nm,而且传输光纤与色散补偿模块的色散斜率不匹配,要实现40通道40 Gbit/s的传输,必须对40个信道分别进行精细的色散补偿。这也说明,对于宽带的40 Gbit/s多波长系统,有必要优化设计或更新传输链路。     

Performance comparison between DCF and RDF dispersion compensation in fiber optical CATV systems

An architecture of an externally modulated AM-VSB CATV 77-channel erbium-doped fiber amplifier (EDFA)-repeated system which use the combination of a single-mode fiber (SMF) and reverse dispersion fiber (RDF) as a dispersion compensation device is proposed and demonstrated. Compared to the conventional externally modulated fiber optical CATV systems with or without a dispersion compensation fiber (DCF), excellent performance of composite second order (CSO) /spl ges/ 78 dB accompanied by satisfied carrier-to-noise ratio (CNR) /spl ges/ 50 dB and composite triple beat (CTB) /spl ges/ 65 dB was obtained in the proposed system.     

通过恒包络调制提高相干光OFDM系统的光纤非线性容限

相干光正交频分复用(CO-OFDM)对光纤链路中 的色度色散(CD)和偏振模色散(PMD)具有较强的容忍性,但 是OFDM信号高峰均功率比(PAPR)的特点使其对光纤非线性效应 非常敏感,严重影响了系统传输性能。 本文提出了基于恒包络(CE)调制的方法使得系统中光信号PAPR降低为0dB,从而提高了CO-OFDM系统的非 线性传输性能。仿真结果表明,子载波采用16QAM调制的40Gbit/s单信道CE调制CO -OFDM系统,在经800km无色散补偿、欠色散补偿和周期全色散补偿 标准单模光纤(SSMF)链 路传输后,虽然较传统CO-OFDM存在约1.8dB的代价,但是系统最大 发射光功率分别提高 了6.2、9.3dB。并且,将本文方案应 用 到CO-OFDM和10Gbit/s NRZ-OOK混合传输WDM系统中,信道最大发 射光功率仍获得了5.2dB的提高。因此,本文提出的CE调制方法能有 效地提高CO-OFDM系统在不同传输环境中的光纤非线性容限。     

波分复用系统的四波混频特性研究

本文对波分复用（WDM）光纤通信系统中的四波混频（FWM）特性进行了研究，得到了WDM可用于由多段不同长度，不同色散值的光纤组成的多级放大WDM系统FWM效应的计算方法，进而分析了单级、多级放大和色散补偿这3种特例的FWM特性，研究结果表明，标准单模光纤与高负色散值色散移位光纤的组合可以有效地抑制FWM混频效应。     

Dispersion compensation optical fiber modules for 40 Gbps WDM communication systems

Dispersion compensation was originally proposed to equalize pulse distortion.With the development of wavelength division multiplexing (WDM) techniques for large capacity optical communication systems,dispersion compensation technologies have been applied into the field.Fiber-based dispersion compensation is an attractive technology for upgrading WDM communication systems because of its dispersion characteristics and good compatibility with transmission optical fibers.Dispersion compensation fibers and the modules are promising technologies,so they have been receiving more and more attention in recent years.In this work,high performance dispersion compensation fiber modules (DCFMs) were developed and applied for the 40 Giga bit-rate systems.First,the design optimization of the dispersion optical fibers was carried out.In theory,the better the refractive index profile is,the larger the negative dispersion we could obtain and the higher the figure of merit (FOM) for the dispersion optical fiber is.Then we manufactured the fiber by using the plasma chemical vapor deposition (PCVD) process of independent intellectual property rights,and a high performance dispersion optical fiber was fabricated.Dispersion compensation fiber modules are made with the dispersion compensating fibers (DCFs) and pigtail fibers at both ends of the DCFs to connect with the transmission fibers.The DCFMs present the following superior characteristics:low insertion loss (IL),low polarization mode dispersion,good matched dispersion for transmission fibers,low nonlinearity,and good stability for environmental variation.The DCFMs have the functions of dispersion compensation and slope compensation in the wavelength range of 1525 to 1625nm.The experiments showed that the dispersion compensation modules (DCMs) met the requirements of the GR-1221-CORE,GR-2854-CORE,and GR-63-CORE standards.The residual dispersions of the G.652 transmission lines compensated for by the DCM in the C-band are less than 3.0ps/nm,and the dispersion slopes are also compensated for by 100%.With the DCFMs,the 8×80km unidirectional transmission experiments in the 48-channel 40Gbps WDM communication system was successfully made,and the results showed that the channel cost was smaller than 1.20dB,without any bit error.