1. Dense Wavelength Division Multiplexing Theory

2. What we will cover WDM Overview Optical Fiber Transmission Characteristics Key technologies of DWDM Technical Specifications

3. Background WDM TDM SDM

4. PDH SDH DWDM 155M622M2.5G10G G.957G.691 G.692 PDH, SDH and DWDM

5. IP ATM SDH DWDM Physical Fiber DWDM Physical Fiber Open Optical Interface SDH ATM IP Other Relationship between DWDM and Other Services

6. WDM Definition WDM enables transmitting multiple optical carriers with information (analog or digital) on one fiber N 2 1 N 2 1 N 2 1 OMU ODU OA

7. DWDM Concept Dense wavelength division multiplexing (DWDM) Power ( dBm) 1529 - 1560nm λ(nm) wavelength interval ： 0.8 ～ 2nm

8. DWDM System OTU1 ┇ Input Ch 1 Ch N Ch 1 Ch N λ1λ1λ1λ1 λnλnλnλn OTUn OMU BA LA PA ODU λ1λ1λ1λ1 λnλnλnλn OTU1 ┇ OTUn λs λs λs λs OSC OSCOSC Output EMS Optical Transmitter OLA Optical Receiver

9. Common Network Elements in DWDM Optical Terminal Multiplexer (OTM) Optical Line Amplifier (OLA) Optical Add/Drop Multiplexer (OADM)

10. Optical Terminal Multiplexer (OTM) Client side Line side λ1λ1 λnλn λ1λ1 λnλn OTM At the transmitter end, the OTM: Multiplexes the STM-N signals of “N” wavelengths λ 1 ~λ N into a DWDM main optical channel Amplifies the optical power of the main channel via the multiplexer Adds an optical supervisory channel λ s At the receiving end, the OTM: Extracts the optical supervisory channel λ s DWDM main optical channel is amplified and de-multiplexed into STM- N signals of the N different wavelengths

11. Optical Line Amplifier (OLA) OLA is configured in each direction of the fiber link OLA extracts the optical supervisory channel (OSC) and processes it It then amplifies the main optical channel signals, multiplexes them with the optical supervisory channel and sends them onto the fiber Line side OLA

12. Optical Add/Drop Multiplexer (OADM) OADM performs add/drop of wavelengths Client side Line side λ1λ1 λnλn λ1λ1 λnλn OADM

13. Operational Wavelength Range O BandOriginal1260-1360 nm E BandExtended1360-1460 nm S BandShort1460-1530 nm C BandConventional1530-1565 nm L BandLong1565-1625 nm U BandUltralong1625-1675 nm

14. Division Of Low-Loss Window

15. Feature Comparison between Low-Loss Windows WindowIIIIIIIVV Mark (nm)850 1310 (O band) 1550 (C band)1600 (L band) 1360 ~ 1530 (E + S bands) Wavelength range (nm) 600~9001260~13601530~15651565~1625 1360~1530 Fiber typeMMF MMF/G.652/ G.653 G.652/G.653/ G.655 Full-wave fiber Applications Short distance and low rate Long distance and high rate

17. Wavelength Allocation On C-Band No.Central Frequency (THz)Wavelength (nm) 1192.11560.61 2192.21559.79 3192.31558.98 4192.41558.17 5192.51557.36 6192.61556.55 7192.71555.75 8192.81554.94 9192.91554.13 10193.01553.33 11193.11552.52 12193.21551.72 13193.31550.92 14193.41550.12 15193.51549.32 16193.61548.51 17193.71547.72 18193.81546.92 19193.91546.12 20194.01545.32 40 Channels / 100 GHz interval

18. Wavelength Allocation On C-Band 40 Channels / 100 GHz interval 21194.11544.53 22194.21543.73 23194.31542.94 24194.41542.14 25194.51541.35 26194.61540.56 27194.71539.77 28194.81538.98 29194.91538.19 30195.01537.40 31195.11536.61 32195.21535.82 33195.31535.04 34195.41534.25 35195.51533.47 36195.61532.68 37195.71531.90 38195.81531.12 39195.91530.33 40196.01529.55

19. TDM Electrical Regenerator for Single Wavelength DWDM Multi-wavelength on Single Fiber, for Optical Amplification DWDM vs. SDH T T R R 1 Electrical MultiplexElectrical Demultiplex TransmitterReceiver Electrical Regenerator N 2 1 N 2 1 N 2 1 Optical Multiplexer Optical Demultiplexer OA

20. DWDM Features Large transparent transmission capacity greatly saves fiber resources Each wavelength can carry different signal: SDH 2.5Gbps, 10 Gbps, ATM, IP DWDM technology provides multiple virtual fiber channels in one physical fiber channel SDHDWDM

21. DWDM Features Through super-long distance transmission technologies, the transmission cost is reduced SDH DWDM Electrical Regenerator Light Amplifier

22. DWDM Features 8*2.5G 32*2.5G 16*2.5G 32*10G

23. Key technologies of DWDM

24. DWDM System OTU1 ┇ Input Ch 1 Ch N Ch 1 Ch N λ1λ1λ1λ1 λnλnλnλn OTUn OMU BA LA PA ODU λ1λ1λ1λ1 λnλnλnλn OTU1 ┇ OTUn λs λs λs λs OSC OSCOSC Output EMS Optical Transmitter OLA Optical Receiver

25. Key Technologies Of DWDM Optical Source Optical Multiplexer And De-multiplexer Optical Amplifiers The Supervision Of WDM System

26. Optical Source Requirements of optical sources: Larger dispersion tolerance value Standard and stable wavelength Types of optical sources: Light Emitting Diode (LED) Laser Diode (LD)

27. Optical Multiplexing and De-multiplexing Technology

28. Optical Multiplexer and Demultiplexer Multiplexer Fiber Demultiplexer

29. Supervision System Technology

30. Supervision System Detection, control and management are basic requirements of all network operations To ensure secure operation of DWDM system, physically, the monitoring system is designed as an independent system separated from working channels and devices Used to transmit the NE management and supervision information related to DWDM system

31. Functions Fault alarm Fault location Quality parameter supervision in the operation Control over backup line upon line interruption EDFA supervision

32. Optical Supervision Control (OSC) OMUODU OBA OPA OBA ODUOMU OLA OSC

33. Optical Supervision Control (OSC) 1510nm Signal speed :2.048Mb/s Receiving sensitivity :-48dbm Transmission power :0 ~ -7 dbm

34. THANK YOU