1、 2010 Cisco and/or its affiliates. All rights reserved.Cisco ConfidentialPresentation_ID 1 2007 Cisco Systems, Inc. All rights reserved.Cisco ConfidentialPresentation_ID1 光傳輸原理培訓 2010 Cisco and/or its affiliates. All rights reserved.Cisco ConfidentialPresentation_ID 2 2 2 內容內容 光傳送技術基礎 DWDM傳輸技術基礎 ONS

2、15454 Automatic Laser Shutdown CTC 2010 Cisco and/or its affiliates. All rights reserved.Cisco ConfidentialPresentation_ID 3 一、光一、光傳傳送技送技術術基基礎礎 2010 Cisco and/or its affiliates. All rights reserved.Cisco ConfidentialPresentation_ID 4 光光傳輸傳輸系系統統基本模型基本模型 光信源(發送器) 光信道(光纖) 光信宿(接收機) Optical fiber pair RX

3、 Optical transmitter Optical receiver TX Transmission 2010 Cisco and/or its affiliates. All rights reserved.Cisco ConfidentialPresentation_ID 5 光信源 Optical Transmitters 2010 Cisco and/or its affiliates. All rights reserved.Cisco ConfidentialPresentation_ID 6 Optical Transmitters Multiple optical tra

4、nsmitters are used as the light sources in a DWDM system. Incoming electrical data bits (0 or 1) trigger the modulation of a light stream Example: a flash of light = 1, the absence of light = 0 Lasers create pulses of light Each light pulse has an exact wavelength or lambda expressed in nanometers (

5、nm) 2010 Cisco and/or its affiliates. All rights reserved.Cisco ConfidentialPresentation_ID 7 Optical Transmitter Block Diagram Detects pulses of electrical charge Power measured in watts (W) Amplitude measured in volts (V) Creates pulses of light Power measured in decibel-milliwatts (dBm) Relative

6、amplitude measured in decibels (dB) Electrical conductor E-O Optical fiber 1 11 0 1 11 0 Electrical-to-optical (E-O) conversion + - dB + - V + - 2010 Cisco and/or its affiliates. All rights reserved.Cisco ConfidentialPresentation_ID 8 Wavelength Windows Conventional optical networks operate with wav

7、elengths from three “windows” centered around: 850 nm (LED) 1310 nm (LED or laser) 1550 nm (high-quality laser) 850 nm1310 nm1550 nm Tight wavelength tolerance 2010 Cisco and/or its affiliates. All rights reserved.Cisco ConfidentialPresentation_ID 9 光信宿Optical Receivers 2010 Cisco and/or its affilia

8、tes. All rights reserved.Cisco ConfidentialPresentation_ID 10 Optical Receivers Detect pulses of light on an optical fiber Convert optical signals into electrical signals for processing Wideband devices Detect optical signals within a wide range of wavelengths 2010 Cisco and/or its affiliates. All r

9、ights reserved.Cisco ConfidentialPresentation_ID 11 Optical Receiver Block Diagram Detects pulses of light Power measured in decibel-milliwatt (dBm) Relative amplitude measured in decibels (dB) Creates pulses of electrical charge Power measured in watts (W) Amplitude measured in volts (V) Electrical

10、 conductor O-E Optical fiber + - Optical-to-electrical (O- E) conversion 1 11 0+ - dB 1 11 0 + - V 2010 Cisco and/or its affiliates. All rights reserved.Cisco ConfidentialPresentation_ID 12 Receiver Specifications Receivers are classified by the characteristics of the detected optical signals. Wavel

11、ength range (nm) Signal power minimum/maximum (dB) Signal dispersion tolerance (ps/nm) OSNR tolerance (dB) 2010 Cisco and/or its affiliates. All rights reserved.Cisco ConfidentialPresentation_ID 13 一、光信道一、光信道 Core（核心（核心層層）：）： 攜帶光信號 Cladding（包（包層層）：）：包層和核心對光信號 的折射率不同，使得光信號在核心層中 傳送 Coating（保（保護層護層）：）：

12、 保護玻璃材料 Coating 250 microns 光纖由三部分組成： Cladding 125 microns Core SMF 8 microns 2010 Cisco and/or its affiliates. All rights reserved.Cisco ConfidentialPresentation_ID 14 n2 n1 Cladding Core n2 n1 Cladding Core Different Types of Fiber 多模光纖 Core diameter varies 50 um for step index 62.5 um for graded

13、index Bit rate-distance product 500 MHz-km 單模光纖 Core diameter is about 9 um Bit rate-distance product 100 THz-km 2010 Cisco and/or its affiliates. All rights reserved.Cisco ConfidentialPresentation_ID 15 一、光信道一、光信道 2010 Cisco and/or its affiliates. All rights reserved.Cisco ConfidentialPresentation_

14、ID 16 光通信用的是紅外光 850 nm：多模 1310 nm：單模 C-band:1550 nm：單模長距離傳輸（用于波分系統） L-band: 1625 nm：單模（用于波分系統） 紫外光紅外光 850 nm 1310 nm1550 nm1625 nm l 一、光一、光纖纖通信與光通信與光譜譜 可見光 2010 Cisco and/or its affiliates. All rights reserved.Cisco ConfidentialPresentation_ID 17 衰減：Attenuation 信號強度降低 色散：Chromatic Dispersion (CD) 非線

15、性效應 Nonlinear Effects 光信噪比：Optical Signal to Noise Ratio (OSNR) 噪聲在信號中所占有的比例 二、光信號的二、光信號的傳輸損傷傳輸損傷 2010 Cisco and/or its affiliates. All rights reserved.Cisco ConfidentialPresentation_ID 18 TT Pi P0 衰減：衰減：Attenuation Pulse amplitude reduction limits “how far” Attenuation in dB=10 xLog(Pi/Po) Power is

16、 measured in dBm: P(dBm)=10 xlog(P mW/1 mW) Examples 10 dBm10 mW 0 dBM1 mW 3 dBm500 uW 10 dBm100 uW 30 dBm1 uW ) 2010 Cisco and/or its affiliates. All rights reserved.Cisco ConfidentialPresentation_ID 19 衰減：衰減：Attenuation Light loss in fiber is caused by two things Absorption 吸收by the fiber material

17、 Scattering 散射of the light from the fiber Light loss causes signal attenuation Rayleigh Scattering Scattering 850 nmHighest 1310 nmLower 1550 nmLowest 2010 Cisco and/or its affiliates. All rights reserved.Cisco ConfidentialPresentation_ID 20 Other Causes of Attenuation in Fiber MicrobendsCaused by s

18、mall distortions of the fiber in manufacturing MacrobendsCaused by wrapping fiber around a corner with too small a bending radius Back reflectionsCaused by reflections at fiber ends, like connectors Fiber splicesCaused by poor alignment or dirt 2010 Cisco and/or its affiliates. All rights reserved.C

19、isco ConfidentialPresentation_ID 21 當光衰減大到一定程度后，接收端的光設備將無法接收到光信號 光卡的發送功率和接收靈敏度 插入損耗(dB) Attenuation (dB) 距離 (km) Optical device 三、三、光信號衰減光信號衰減 2010 Cisco and/or its affiliates. All rights reserved.Cisco ConfidentialPresentation_ID 22 8009001000110012001300140015001600 OH- Absorption Peaks in Actual

20、Fiber Attenuation Curve Wavelength in Nanometers (nm) 0.2 dB/Km 0.5 dB/Km 2.0 dB/Km (dB)/km vs. Wavelength S-band:14601530nm L-band:15651625nm C-band:15301565nm 三、光三、光纖纖衰耗特性衰耗特性 2010 Cisco and/or its affiliates. All rights reserved.Cisco ConfidentialPresentation_ID 23 三三、 、不同光不同光纖類纖類型的典型衰耗型的典型衰耗 201

21、0 Cisco and/or its affiliates. All rights reserved.Cisco ConfidentialPresentation_ID 24 影響光預算的因素: 光纖損耗：1310nm（0.4dB/km)、1550（0.2dB/km） 光纖熔合 Export Right-click an alarm to view affected circuits From any view the Alarm Tab shows a list of all alarms (CR, MJ, MN) and conditions (NA) for the network, N

22、E, or card (depending on the selected view). The view determines the scope of the alarm reports, e.g. card view shows only card alarms. Correlated alarms are not shown but can be viewed in the Conditions tab 2010 Cisco and/or its affiliates. All rights reserved.Cisco ConfidentialPresentation_ID 70 A

23、larm Reporting and History / 3 From the selected view History tab you can view the alarm history for the network, node, shelf, or card. The selected view determines the scope of the history, e.g. at card view only the card history is shown. Alarm history is stored on the TCC2/TCC2P so it is availabl

24、e only as long as the TCC is in the shelf (NC or stand-alone) and powered up. If power is lost to a node (NC or stand-alone) the alarm history is also lost. Network View will show alarm history for only the current CTC session. Alarm Filtering works the same for history as for current alarms. The Se

25、ssion tab holds alarm history just since the last login. 2010 Cisco and/or its affiliates. All rights reserved.Cisco ConfidentialPresentation_ID 71 Performance Monitoring (PM) / Filters, Amps, OSC units For DWDM filters, amplifiers, and OSC units an 8-hour (15 min intervals) / 2-day (1 day intervals

26、) optical power history showing min/max/average power (dBm) for the period is available for each port on the card. This is available in Card View Performance. All PM history can be exported in excel or html format. Select a port to monitor on the card, then Refresh For DWDM filters, amplifiers, and

27、OSC units real- time power values are available in Card View Provisioning. Real-time dBm values 8-hours of historical data 15 min period 2006 Cisco Systems, Inc. All rights reserved.Cisco ConfidentialPresentation_ID72 Performance Monitoring (PM) / Interfaces (TXP, MXP, etc) An 8-hour (15 min interva

28、ls) or 2-day (1 day intervals) optical power history showing min/max and average power for the period is available for TX / RX power and Laser Bias. All PMs are available in Card View Performance. All PM history can be exported in excel or html format. Select a port to monitor, then Refresh Real-tim

29、e values for each port can be viewed from Current Values tab Interfaces report payload PMs including payload Statistics/Parameters, Utilization (for data payloads), and Statistics History (for data payloads). All PM values are available in Card View Performance. All reported values can be exported i

30、n excel or html format. All G.709-capable interfaces (except 2.5G Datamux) report related G.709 and FEC PM data. Select a port to monitor, then Refresh 8-hours of historical data 15 min period 2010 Cisco and/or its affiliates. All rights reserved.Cisco ConfidentialPresentation_ID 73 Performance Monitoring / Threshold Crossing Alerts (TCA) On most cards a threshold crossing alert (TCA) can be set for ports to report a warning when optical or payload p