Corning Incorporated · NYSE:GLW
Corning — Technical Presentation (August 2003)
25 slides from Corning's technical presentation, Aug 27, 2003
Slide 1: Link Polarization Mode Dispersion Understanding and Its Usage for System Design
Link Polarization Mode Dispersion Understanding and Its Usage for System Design 链路偏振模色散的理解与其在系统设计之应用 李懋循 博士 亚洲区技术总监 美国康宁公司光纤部 2003年8月27日
Slide 2: Outline
Outline 提纲 • Why is PMD important? 偏振模色散为什么重要? • Define polarization mode dispersion (PMD) 偏振模色散(PMD)的定义 • PMD impact on next-generation LH systems PMD 对下一代长途传输系统的影响 • Specifying and controlling PMD performance PMD 特性的指定与控制 • How to utilize PMDQ for system design 如何应用 PMDQ 于系统设计 • Case Study 案例研究 •
Slide 3: Differential Group Delay (DGD)
Differential Group Delay (DGD) 微分群时延(DGD) • Asymmetry in the refractive index (birefringence) creates a delay between the PSP called Differential Group Delay 折射率的不对称(双折射)会产生在主偏振态间的时延称为微分群时延 Instantaneous Slow PSP DGD 瞬时DGD 慢速主偏振态 Output Input Intensity Intensity Differential Group 输出光强度 输入光强度 Fast P
Slide 4: PMD Is Average of DGD
PMD Is Average of DGD 偏振模色散是DGD的平均 • Due to random mode coupling along the propagation direction instantaneous DGD is random in both time and wavelength 由于在传输方向的随机模耦合,瞬时DGD在时间和波长上 都是随机变化 DGD vs wavelength DGD vs wavelength 0.6 0.6 0.5 0.5 0.4 ps/sqrt(km) 0.4 ps/sqrt(km) 0.3 0.3 0.2 0.2 0.1 DGD 0.1 D
Slide 5: Historical Worst Case Approach: PMDmax
Historical Worst Case Approach: PMDmax 过去最坏情况的方法:最大偏振模色散(PMDmax) • Outage Probability: 13.25 min /yr/ circuit (99.9974%) 系统故障概率:13.25 分/年/线路 (99.9974%) • Full 1 dB power penalty (0.5 dBQ) at Rx (assume all due to PMD) 接收器 1 dB 的功率损耗(0.5 dBQ) (假设全部归属PMD) • 400 km reach 400公里的传输距离 Bit Rate Link PMDmax
Slide 6: PMD Statistical Specifications
PMD Statistical Specifications PMD 的统计指标 • IEC TR 61282-3 and IEC 60794-3 document outline two statistical methods IEC TR 61282-3 及 IEC 60794-3 两份文件概述了两种统计方法 – Method 1 produces a statistical upper bound (PMD link value) based on a number of concatenated fibers/cables and an associated probability 方
Slide 7: Merit of Statistical Approach
Merit of Statistical Approach 统计方法的好处 • Standards compliant 标准的符合 – Choice of multiple source 多种器件来源的选择 – Upgrade and future proof 升级和未来的保证 • Statistical design, “state of the art” that allows 统计设计是“最先进”的方法,它允许 – Using full value of product (allows to estimate system PMD) 利用产品的全面价值(可以估计系统的PMD) – Det
Slide 8: Merit of Statistical Approach (continued)
Merit of Statistical Approach 统计方法的好处(接上页) • Statistics provided a path in 10 Gb/s context 统计方法已为 10 Gb/s 情况铺路 – Allowing cable specs of 0.5 ps/√km 允许光缆 PMDQ 指标为 0.5 ps/√km • Statistics are required in 40 Gb/s context 在 40 Gb/s 情况需要用统计方法 – Otherwise there would not be any PMD budget left for compone
Slide 9: Monte Carlo Simulations Provides Statistical PMD Specification: PMDQ
Monte Carlo Simulations Provides Statistical PMD Specification: PMDQ Monte Carlo 模拟提供统计的PMD指标: PMDQ Histogram for Manufactured “Method 1” Frequency Fiber PMD 生产光纤偏振模色散直方图 “方法 1” Frequency Fiber PMD PMDQ Link PMD Link M sections 段 试验次数 # trials > 100,000 PMD Define PMDQ (Link Design Value) as an uppe
Slide 10: Link Design Value (PMDQ) Is A Better Estimate Of Concatenated Link PMD
Link Design Value (PMDQ) Is A Better Estimate Of Concatenated Link PMD 链路设计值为串接光纤链路PMD较好的估计 • PMDmax is an overly conservative estimate of the PMD of a link consisting of concatenated fibers PMDmax 作为对由串接光纤组成链路的PMD是过于保守估计 Individual Fiber PMD Distribution Frequency 个别光纤PMD的分布 Concatenated Fiber link
Slide 11: ITU Recommendations (G.652 & G.655)
ITU Recommendations (G.652 & G.655) ITU 建议(G.652 & G.655 光纤) • “When require, cabled fibre polarisation mode dispersion shall be specified on a statiscal basis, not on an individual fibre basis” “当有需要时,成缆光纤的PMD应该用统计为基础指定而不是 用个别光纤为基础” • Annex B - 10 Gb/s transmission and 400km reach system 附录 B - 10
Slide 12: Maximum Acceptable Probability of System Outage Sets Maximum Link DGD
Maximum Acceptable Probability of System Outage Sets Maximum Link DGD 用系统故障最大可接受的概率来设置链路DGD最大值 PMDlink “Method2” 方法2 Probability of Outage 故障概率 (DGD > DGDmax) or, circuit availability 或线路有效率 P(DGD) P > 99.99999 % “7 nines” 7个9 = 0.04 min/ yr / circ 分 / 年 / 线路 DGDmax < 3.70 × PMDLink S = DGD / PMDlin
Slide 13: Probability Implications
Probability Implications 概率的含意 • 5-nines (99.999%) circuit availability is a typical requirement for all sources and causes 一般线路有效率对所有故障来源和起因的要求是 5 个 9 (99.999%) • PMD must be somewhere near 7-nines (99.99999%), this translates to circuit unavailability of 0.04 min/year/circuit that implies 对PMD而言一定
Slide 14: Concatenation with Components
Concatenation with Components 与器件串接 • IEC TR 61282-3 (two approaches, 2nd favored) IEC TR 61282-3 (两种方法,方法 2 一般较为赞同) 1/ 2 DGD max tot = DGD max 2F + S 2 ∑ PMDCi2 + ∑ DGD max Dj i j 1/ 2 DGD max tot = DGD max F + S ∑ PMDCi + ∑ PMDDj 2 2 2 2 i j P(DGDtot > DGD max
Slide 15: Given PMDQ, What Is DGDmax?
Given PMDQ, What Is DGDmax? 在给定的PMDQ, 什么是 DGDmax? • Just using the equation S = DGD / PMDlink is not sufficient 仅用公式 S = DGD / PMDlink 是不充分的 • Many PMD distributions pass PMDQ with various average link PMD that also affects system performance 许多PMD的分布能通过 PMDQ 指标却具有影响系统性能的 不同总平均链路PMD Various Variousp
Slide 16: Convolution – Theory of Method 2
Convolution – Theory of Method 2 结合理论为方法 2 的基础 • Convolution yield different PMD i,average values for these distributions with the same maximum PMDQ 在这些不同 PMD 分布具有相同的最大 PMDQ, 方法 2 的结合理论产生 许多不同 PMD i,average 值 Relative frequecy PMD2,average 0.07 0.06 0.05 0.04 PMD1, average ∝ 2 β2 0.03 0.02 ∝2 β1 0.0
Slide 17: Equivalence Plot
Equivalence Plot 等效性图 Equivalence envelopes for Method 1/2 defaults 方法1 和方法2 预设的等效性包封 0.8 0.7 1/2sqrt(beta) (ps/sqrt(km)) 0.6 0.5 0.4 0.3 0.2 0.1 0 0 0.1 0.2 0.3 0.4 Quadrature ave rage (ps /s qrt(k m )) M2: 25 ps, Pr: 6.5e-8, 400 km, 10km cable M1: 0.5 ps/sqrt(km), Pr: 1e-4, 20 cables Corning Restr
Slide 18: 10 Gb/s NRZ, APD (ITU G.691)
10 Gb/s NRZ, APD, ( ITU G.691) 10 Gb/s 不归零码系统,APD,( ITU G.691) 1 dB power penalty, total DGDmax = 30 ps, 1 dB 功率损耗,总 DGDmax = 30 ps • PMDQ ≤ 0.2 ps/√km - allows 2000 km reach PMDQ ≤ 0.2 ps/√km – 可以传输 2000 公里距离内含 – 2000 km with DGD max (cable) ≤ 19.0 ps 2000 公里光缆 DGD max ≤ 19.0 ps – 21 repeaters: 1.3
Slide 19: 10 Gb/s NRZ, APD (ITU G.691) (continued)
10 Gb/s NRZ, APD, ( ITU G.691) 10 Gb/s 不归零码系统,APD,( ITU G.691)(接上页) • PMDQ ≤ 0.10 ps/√km - allows 4000 km reach PMDQ ≤ 0.10 ps/√km – 可以传输 4000 公里距离内含 – 4000 km with DGD max (cable) ≤ 12.0 ps 4000 公里光缆 DGD max ≤ 12.0 ps – 25 km cable section lengths 25 公里长的光缆段 – 41 repeaters: 1.13 ps/unit 41 个中继器:每单元
Slide 20: Compare with Worst Case Approach (ITU G.691)
Compare with Worst Case Approach, ( ITU G.691) 与最坏情况方法的比较,( ITU G.691) 1 dB power penalty, total DGDmax = 30 ps, 1 dB 功率损耗,总 DGDmax = 30 ps PMDmax = 0.125 ps/√km • 2000 km: DGDmax (cable) 21 ps 2000 公里光缆 DGDmax : 21 ps – Residual for repeater: 1.23/unit DGD 余留给中继器 : 每单元 1.23 ps • 4000 km: DGDmax (ca
Slide 21: 40 Gb/s, APD – (ITU G.959.1)
40 Gb/s, APD – (ITU G.959.1) 40 Gb/s, APD – ( ITU G.959.1) Assume DGDmax (link) = 11.5 ps (1.0 dB penality for PIN RZ) 假设链路 DGDmax = 11.5 ps (PIN 归零码系统 1.0 dB 功率损耗) • PMDQ ≤ 0.10 ps/√km 400 km 400公里 5.0 ps for cable 光缆 DGDMAX : 5.0 ps 5 repeaters units: 1.22 ps each 5 个中继器单元:每单元 1.22 ps - 2 amps @ 0
Slide 22: Compare with Worst Case Approach (ITU G.959.1)
Compare with Worst Case Approach,( ITU G.959.1) 与 最坏情况方法的比较,( ITU G.959.1) Assume DGDmax (link) = 11.5 ps (1.0 dB penality for PIN RZ) 假设链路 DGDmax = 11.5 ps (PIN 归零码系统 1.0 dB 功率损耗) PMDmax = 0.125 ps/√km • 400 km: DGDmax from cabled fiber is 9.45 ps 400公里: 成缆光纤 DGDmax 为 9.45 ps 5 repeaters: 0.77 ps/u
Slide 23: Summary
Summary 结论 • ITU -T G.652 & G.655 recommend and IEC TR 61282-3, IEC 60794-3 specifies the use of statistical PMDQ specification in cabled fiber ITU -T G.652 及 G.655 建议和 IEC TR 61282-3,IEC 60794-3 文件 指定成缆光纤用统计的PMDQ 指标 • Statistical PMDQ approach 统计PMDQ 的方法 - enables compatibility with future standard
Slide 24: Summary (continued)
Summary 结论(接上页) - allows using full value of product 允许利用产品的全面金额 - allows balancing needs of components, extra PMD budget margin can be used for cheaper components, transparent network elements, longer reach without PMD compensator 允许平衡器件PMD的需求,额外PMD预算余量可提供使用较便宜的器件, 更透明的网络单元,增长的传输距离而不需要PMD补偿器 • Stat
Slide 25: Conclusion
Conclusion 总结 • PMD may seem complicated but the statistical approach allows effective PMD management for system design and cost savings PMD似乎很复杂,但是统计方法可以用有效的PMD处理方法 用于系统设计及节省成本 • Corning is willing to help customers on link PMD understanding and its usage for system design. 康宁公司非常愿意帮助客户了解链路PMD及其在系统