密集波分复用系统中的光纤非线性效应及其影响

本方介绍了光纤非线性效应的各类及其对高速率、长距离密集波分复用(DWDM)系统的影响及解决措施。     

积分法测试光信噪比在密集波分复用中的应用

长距离、高速率(单波40Gb/s)DWDM(密集波分复用)技术在国家干线、省干线系统应用中,为满足端到端信号质量要求,原先用于中短距离系统的NRZ(非归零)码型逐渐被RZ(归零)、ODB(光双二进制)、DQPSK(差分四相相移键控)等码型替代.新的码型具有更宽的信号光谱宽度,这导致用传统光谱仪无法准确测试信号的光信噪比...     

粗波分复用(CWDM)系统及其测试

对粗波分复用技术的产生、发展和应用进行描述，并与密集波分复用技术进行比较，最后介绍了粗波分复用系统的测试及其注意事项。     

光纤通信技术的新发展

通过对光纤通信技术及其关键器件技术（诸如波分复用、带宽光放大、可调谐光源、偏振模色散补偿等技术）、量子保密通信技术近期新发展的全面介绍，指出光纤通信特别是密集波分复用（DWDM）系统向高速率、大容量、性能价格比合理的全光网络的发展趋势。     

关于华为OptiXBWS1600GDWDM光传输系统的特点论述

21世纪信息时代的到来使得IT技术发展迅速,各行各业在满足本行业应用需求的同时或多或少都会与信息系统有所交集!华为Opti XBWS1600G骨干DWDM光传输系统作为一款高速率、大容量密集波分复用传输系统,拥有诸多同行业系统所不具备的超常优势,使得其在全球范围内获得规模应用!     

光纤通信技术的新发展

通过对光纤通信技术及其关键器件技术（诸如波分复用、带宽光放大、可调谐光源、偏振模色散补偿等技术）、量子保密通信技术近期新发展的全面介绍；指出光纤通信特别是密集波分复用（ＤＷＤＭ）系统向高速率、大容量、性能价格比合理的全光网络的发展趋势。     

非零色散位移单模光纤应用的探讨

近年来开发的非零色散位移单模光纤改进了高速率密集波分复用中的传输性能。文章简单介绍了这种光纤的特性和一些应用实例,并对在我国通信发展中的应用作了分析和探讨。     

40 Gbit/s波分复用系统光转发单元的实现

利用子速率复用方案,研制了40Gbit／s密集波分复用系统的光转发单元,并进行了测试,测试结果表明该单元达到了设计要求。     

全光纤DWDM器件的研制

介绍了在密集波分复用系统中使用的一种全光纤波分复用解复用器件的原理,分析了第二个耦合器耦合比对信道隔离度的影响,给出了制作全光纤密集波分复用解复用器件的实验数据。     

DWDM系统及其线路传输系统的设计

简要介绍密集波分复用系统在光纤光缆传输网中的应用及其发展趋势。密集小分复用系统的类型,系统容量,传输方式及传输系统设计。     

100/200 Gb/s数字相干光模块的光信噪比测试

线路侧光模块CFP2-DCO在4G/5G网络建设中具有重要而广泛的应用,而光信噪比(OSNR)指标是评估其性能的重要参数。光纤通信系统中的偏振模色散(PMD)及色度色散(CD)的干扰,对OSNR性能有重要的影响,PMD及CD的干扰对系统OSNR造成的劣化即为PMD、CD的OSNR代价。探讨了OSNR的不同测试方法,并针对通信设备制造商在实验室对OSNR进行测试的需求,搭建了一种OSNR及PMD、CD干扰代价的自动化测试平台。利用该平台对CFP2-DCO的OSNR及PMD、CD的OSNR代价进行了测试,并进一步测试得到叠加PMD、CD干扰后的OSNR代价及PMD、CD与OSNR的关系曲线。测试结果表明:PMD、CD的干扰越大,通信系统对OSNR的要求越高,因此应尽量降低系统的PMD、CD干扰,从而可以优化系统性能,提高通信质量。     

N×40 Gbit/s波分系统在线带内信噪比测试方法研究与验证

在40Gbit/s和ROADM波分系统中,传统的信噪比测试方法已不适用,需要进行带内信噪比测试。积分法虽然可以测试带内信噪比,但由于需要反复打开和关闭信号光,并且每次只能测试一个通道,不适于系统测试。目前的偏振法具有多种类型,本文重点讨论了混合偏振差分光谱分析法的原理,并且进行了实际的验证测试。     

偏振分光法光信噪比监测技术研究

偏振分光法是基于偏振特性分离信号和噪声的光信噪比(OSNR)监测技术,光纤的非线性效应和偏振模色散会引起传输信号偏振态的改变,影响OSNR的测量准确性.在介绍偏振分光法工作原理和设计流程的基础上,定量分析了非线性效应对偏振分光法测量精度的影响,最后提出了一种附加光滤波器的双通带偏振分光法OSNR测量方案,仿真实验证明该测量方法可提高OSNR的测量精度.     

ASE噪声偏振化对偏振分光光信噪比监测的影响

偏振相关损耗(PDL)引起的自发辐射(ASE)噪声偏振化是导致偏振分光方法监测光信噪比(OSNR)不准确的重要因素,分别研究了ASE噪声与信号偏振平行和偏振正交2种情况下OSNR监测的误差,推导得出了误差计算公式并通过仿真实验得到验证.理论分析和信真实验结果表明:测量误差随着ASE噪声偏振度(DOP)的增加而变大,且与待测信道本身的OSNR基本无关;比较而言,ASE噪声与信号偏振平行时对监测的影响更严重.当与信号偏振平行的ASE噪声的DOP为0.75时,误差值达6 dB.     

Fast on-line OSNR measurements based on polarisation-nulling method with downhill simplex algorithm

A fast on-line OSNR measurement technique which uses the downhill simplex algorithm as a minimum finder is proposed and tested in CW signals for different OSNR levels with excellent agreement. The method is shown to be stable after 8 h of uninterrupted operation and is not affected by environmental temperature change during the test.     

Extracting OSNR From Low-Resolution Optical Channel Monitors

Optical channel monitors (OCMs) that use scanning filters need to resolve the amplified spontaneous emission (ASE) noise floor between channels in order to determine optical signal-to-noise ratio (OSNR). We show how regularized least-squares can extract accurate OSNR values from raw spectra when the ASE floor is not visible because of insufficient resolution in the monitor. Our experimental results demonstrate OSNR measurement accuracy to within 0.6 dB from a spectrum of 50-GHz-spaced 10-Gb/s channels measured using a scanning Fabry-Peacuterot filter with 35-GHz bandwidth. The ability to use broader bandwidth filters in OCMs without sacrificing accuracy may reduce their cost and increase their robustness     

Regularization Techniques for Extracting OSNR From Low Resolution WDM Channel Monitors

Channel monitors that are based on scanning the wavelength division multiplexing (WDM) spectrum with a tunable filter must have sufficient resolution to resolve the ASE floor between channels to enable the OSNRs to be determined. If the bandwidth of the scanning filter is too broad then adjacent channels in the measurement become smeared together thus obscuring this level of ASE. However, in practice it is desirable to use as broad a filter as possible since this will increase mechanical robustness and reduce cost. In this paper, we describe and experimentally demonstrate a signal processing technique that can successfully extract the OSNR out of such smeared measured spectra. Such inverse problems are notoriously ill-posed. To deal with this our technique employs two stages of Tikhonov regularization and uses the known spectral response of the scanning filter together with the knowledge of the expected spectral structure of a single channel. As with all ill-posed inverse problems it can be expected that the extracted OSNR would be extremely sensitive to measurement errors and inaccuracies in the known filter and expected channel shapes. We investigate the sensitivities in OSNR to such errors and our results show the technique to be fairly robust, yielding uncertainties in OSNR below 1 dB over a wide range of realistic system noise levels and spectral variations.     

用偏振模色散模拟器加偏振片实现带内光信噪比检测

提出了一种基于偏振模色散(PMD)模 拟器加偏振片的带内检测光信噪比(OSNR)的方法,理论分析了检测方 法的工作原理,证明了方法不受光纤链路色散和PMD的影响,并且与信号偏振态 、调制格式及传输 速率无关。测试结果表明:在9dB到34dB的测量范围 内,本文检测方 法的测量误差在0.5dB内;在1dB的测量误差范围内,对偏振相关损 耗(PDL)的容忍范围为1dB。     

一种基于偏振的PMD不敏感OSNR监测技术

在分析偏振模色散(PMD)引起传输信号去偏振导致偏振分光光信噪比(OSNR)监测方法测量误差问题的基础上,提出一种用扰偏振器和偏振分束器来克服PMD影响,实现OSNR精确监测的方案.波分复用传输信号经扰偏振器扰偏后解复用分离出待测信道信号,偏振分束器将待测信号分成偏振正交的两个支路信号,然后通过检测到的两支路信号功率之间的关系来得到信道的OSNR.仿真实验证实了新方法对PMD影响不敏感.     

An OSNR monitor for optical packet switched networks

Optical packet switched networks bring about new challenges to the research in optical performance monitoring. We present the first experimental demonstration of an optical signal-to-noise ratio (OSNR) monitor capable of direct OSNR monitoring on the packet basis. By measuring the radio frequency noise from optical packets with a special performance monitoring segment, the OSNR monitoring error is found to be less than 0.6dB for consecutive packets with varying OSNR of 16 to 27 dB. The response time of the OSNR monitor can be around 10 ns.