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.     

基于偏振实现OSNR和PMD的同时监测

在介绍偏振度(DOP)监测方法工作原理,分析偏振模色散(PMD)导致传输信号去偏问题的基础上,提出了一种采用扰偏器和偏振分束器实现光信噪比(OSNR)和PMD同时监测的方案.波分复用传输信号经扰偏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,然后通过检测两支路信号功率之间的关系得到信道的OSNR和PMD值,系统中使用了电放大器,以提高监测灵敏度.     

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.     

PM-QPSK相干系统中改进的OSNR监测方法

针对100Gbit/s及以上PM-QPSK(偏振复用正交相移键控)相干光通信系统,提出了一种改进的基于统计矩的带内OSNR(光信噪比)监测方案,并在搭建的100Gbit/s PM-QPSK相干接收系统中对该方案进行了数值仿真。结果表明,在5~25dB的OSNR范围内,该改进方案对不同占空比的RZ(归零)码调制信号的监测误差均小于0.5dB;根据商用相干接收机对接收端OSNR的要求,取其参考值为14dB,则在0.5dB的监测范围内,对CD(色散)的容忍度为2 400ps/nm,对一阶PMD(偏振模色散)即DGD(差分群时延)的容忍度为62ps。     

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.     

带内OSNR的超高速光传输链路色散在线监测

对现有光传输链路性能监控技术进行了比较,提出了一种基于带内光信噪比、快速灵活的光性能在线监测方法,并进行了建模分析,搭建了色散在线监测系统。对系统性能的主要技术指标进行测试分析的结果表明,该方法进行超高速光传输链路色散在线监测时,与链路数据速率及调制格式均无关,有效实现了传输链路色散在线监测功能。     

高非线性光纤中并行交叉相位调制的偏振膜色散监测方法

利用信号光和插入的连续泵浦光之间产生的交叉相位调制（XPM）效应,提出了一种基于并联的XPM效应来监测光相位调制信号的一阶偏振模色散（PMD）的新技术。泵浦光的光谱会随着信号光中PMD和色散（CD）的变化而发生变化,所以导致泵浦光的光功率发生变化,在并联的一个支路中抑制PMD的影响,利用并联的两路同一波段泵浦光功率的差值来进行监测。仿真结果显示,新的技术可以实现对40 Gb/s非归零差分四相移相键控（NRZ-DQPSK）光信号从0~20 ps的监测。在20 ps的监测范围内,新技术的动态范围大于3 dB,可以用来进行准确的监测。对信号速率、色散、泵浦光功率和滤波器带宽对新技术的影响做了详细的研究。     

高速光纤通信系统中PMD的补偿技术

简要介绍了目前存在的几种PMD补偿技术，分析了各种补偿技术的优缺点，指出了当前PMD补偿所面临的问题．     

2.5 Gb/s偏振模色散自动补偿对偏振模色散容限值的影响

在我国现有的光纤通信骨干网中,绝大部分速率为2.5 Gb/s。今后如在我国现有的2.5 Gb/s网络系统上进行密集波分复用(DWDM)升级,亦需要考虑偏振模色散(PMD)对系统容量升级的影响。采用十段高双折射光纤级联而成的偏振模色散模拟器模拟实际光纤,从信号中提取基带频率分量作为反馈信号,对2.5 Gb/s系统进行了偏振模色散自动补偿实验,并对反馈前后的系统进行了系统代价的测量和比较。实验结果表明,偏振模色散自动补偿能较大幅度地提高系统的偏振模色散容限值。     

光缆制造工艺对偏振模色散（PMD）的影响

随着光纤通信向着数字化、宽带化、智能化方向的迅速发展，光缆被广泛应用在高速率、大容量、宽带宽、长距离的系统中，然而非线性效应和偏振模色散（PMD）却成为系统容量升级和传输距离受限的主要因素，因此受到了运营商和各光缆制造厂家的特别关注。本文就偏振模色散（PMD）的产生机理与光缆制造的各工艺过程对其影响做一简析。     

OSNR Monitoring Method for OOK and DPSK Based on Optical Delay Interferometer

We describe a simple method to measure the optical signal-to-noise ratio (OSNR) of on-off-keying (OOK) and differential phase-shift-keying (DPSK) signals by using an optical delay interferometer (ODI) having a sinusoidal and tunable passband. This OSNR monitoring method is independent of chromatic dispersion, polarization-mode dispersion, and noise polarization. We show experimentally that accurate OSNR measurements are made for a 10-Gb/s OOK signal by using a 1-bit ODI and a 40-Gb/s DPSK signal by using a partial-bit ODI with the OSNR ranging from 5 to 25 dB.     

OSNR Monitoring Technique for DPSK/DQPSK Signals Based on Self-Heterodyne Detection

We describe a new method for monitoring the “in-band” optical signal-to-noise ratio (OSNR) of differential phase-shift-keying (DPSK) and differential quadrature phase-shift-keying (DQPSK) signals. This technique estimates the OSNR by analyzing the radio frequency spectrum obtained by the self-heterodyne detection. The results show that the performance of the proposed technique is not sensitive to the effects of chromatic dispersion and polarization-mode dispersion. In addition, this technique can be used for monitoring the polarization-scrambled signals. For a demonstration, we measure the OSNR of the polarization-scrambled 10-Gb/s DPSK and 20-Gb/s DQPSK signals in a 640-km-long transmission link.      

In-Band OSNR Monitoring Technique Based on Link-by-Link Estimation for Dynamic Transparent Optical Networks

A cost-effective optical performance monitoring system, based on link-by-link optical signal-to-noise ratio (OSNR) estimation, is proposed for a dynamic transparent optical network. The proposed technique estimates the OSNR by monitoring the channel powers at the input and output of each optical link and the total input power to the inline EDFAs. In-band OSNR monitoring was successfully demonstrated at 42.7 Gb/s RZ-DQPSK signals, reflecting the transmission performance.     

基于偏振度椭球的PMD补偿方法的研究

分析了PMD椭球的三个轴随PMD的变化规律,建立了以偏振度椭球的短轴作为PMD补偿的反馈信号的PMD补偿系统模型,并通过数值模拟对一阶和二阶PMD进行了补偿,结果表明采用这种方法能同时有效地补偿一阶及二阶PMD。     

偏振正交外差光信噪比监测技术研究

传统偏振方法监测光信噪比的准确性易受偏振模色散和非线性双折射影响,提出了一种新的偏振正交外差监测方法以克服传统偏振监测方法的缺点.该方法通过将信号分成两个支路并控制偏振态达到相对偏振态正交,用偏振正交的两支路信号外差混频消去信号,通过测量保留下来的差拍噪声实现对光信噪比的监测.仿真试验证实,该方法对偏振模色散和非线性双折射引起的信号偏振态变化不敏感.     

OSNR Margin Brought by Nonlinear Regenerators in the Presence of PMD and Amplified Spontaneous Emission Noise

The behavior of a 2R optical regenerator in a link limited by amplified spontaneous emission (ASE) noise and polarization-mode dispersion (PMD) is investigated in detail in this paper. 2R regeneration techniques are well known for combating the accumulation ASE noise in an optical signal, but their behavior in the presence of PMD is mostly unknown. Here, we propose a general method to calculate the total outage probability in a link including a cascade of optical regenerators. Through the use of semianalytical models, we study the ability of 2R optical regenerators to combat at the same time PMD distortions and ASE noise accumulation in an optical signal, and show their interesting potential to counter independently both detrimental effects.      

In-Band OSNR Monitoring Using Spectral Analysis After Frequency Down-Conversion

A novel method for simultaneous optical signal-to-noise ratio and chromatic dispersion monitoring in wavelength-division multiplexed 40-Gb/s systems is proposed and demonstrated. This technique has a fast response time of <10 ms, applicable to dynamically reconfigurable networks, and is able to simultaneously monitor multiple impairments across multiple channels     

偏振模色散对单模光纤系统的影响

近来,偏振模色散（ＰＭＤ）已成为长距离高速率数据和模拟系统的主要限制因素,本文首先简介ＰＭＤ的原理以及对系统ＰＭＤ的考虑,然后介绍四种ＰＭＤ测量方法的比较,最后介绍了康宁公司的单模光纤在ＰＭＤ方面的优势。