INTRODUCTION TO DWDM 19-Nov-18 ALTTC/TX-I/DWDM

CONTENTS The need for DWDDM Fibre exhaust- alternatives The challenge: Tapping the unlimited fibre bandwidth Achieving the networking functions in the optical domain Wdm approach to fibre exhaust Wdm functional block schematic Differences from conventional system: the amplifier Dwdm systems at present Optical amplifiers Dwdm components Optical bands Standard wavelengths: ITU grid Dwdm applications : Benefit to operators New issues before planners 19-Nov-18 ALTTC/TX-I/DWDM

FIBRE EXHAUST INSTAL HIGHER BITRATE TDM EXPENSIVE, NEW FIBRE NEEDED 2.5- Gbit/s transmitter 2.5-Gbit/s 2.5 Gbit/s reciever 10-Gbit/s 10-Gbit/s 10-Gbit/s transmitter regenerator reciever INSTAL HIGHER BITRATE TDM EXPENSIVE, NEW FIBRE NEEDED 19-Nov-18 ALTTC/TX-I/DWDM

FIBRE EXHAUST DEPLOY DWDM DEMUX MUX 10-Gbit/s transmitter regenerator reciever 2.5- Gbit/s transmitter 2.5-Gbit/s 2.5 Gbit/s reciever λ1 2.5-Gbitt/s transmitter λ1 MUX DEMUX 2.5- Gbit/s reciever λ2 λ2 2.5-Gbitt/s transmitter 2.5- Gbit/s reciever λ3 λ3 2.5-Gbitt/s transmitter 2.5- Gbit/s reciever λ4 λ4 2.5-Gbitt/s transmitter 2.5- Gbit/s reciever DEPLOY DWDM 19-Nov-18 ALTTC/TX-I/DWDM

EVOLUTION OF DWDM Late 1990’s 64-160 channels 25-50 GHZ spacing Mid Dense WDM, integrated systems with Network Management, add-drop functions. Early 1990’s 2-8 channels passive WDM 200-400 GHz spacing WDM components/parts Late 1980’s 2 channels Wideband WDM 1310 nm, 1550 nm 19-Nov-18 ALTTC/TX-I/DWDM

THREE POSSIBLE SOLUTIONS ACHIEVING HIGHER BANDWIDTH THREE POSSIBLE SOLUTIONS INSTAL NEW FIBRE INVEST IN NEW TDM TECHNOLOGIES TO ACHIEVE HIGHER BANDWIDTH. DEPLOY DWDM EXPENSIVE VERY REQUIRE NEW TYPE FIBRE ECONOMICAL 19-Nov-18 ALTTC/TX-I/DWDM

THE CHALLENGE:Continuous growth in traffic… Calls for tapping the unutilized bandwidth of the media ACHIEVE NETWORKING FUNCTIONS (ROUTING etc) IN OPTICAL DOMAIN JUST LIKE WIDENING OF ROAD USING AVAILAB.E LAND TO MEET INCREASED TRAFFIC 19-Nov-18 ALTTC/TX-I/DWDM

DWDM BASICS NEW REQUIREMENTS: MULTIPLEXER DWDM SDH OPTICAL SIGNALS SINGLE FIBRE SDH OPTICAL SIGNALS NEW REQUIREMENTS: 19-Nov-18 ALTTC/TX-I/DWDM

BLOCK SCHEMATIC Tx Rx OFA DEMUX MUX W D M W D M OPTICAL SIGNALS. 1 STM-1 STM-4 STM-16 ATM IP W D M 2 . 1 16 W D M TRANSPONDERS 19-Nov-18 ALTTC/TX-I/DWDM

Wayside Optical Add/Drop Multiplexer TM TM WDM MUX WDM DEMUX  2 15 16 1  1-4 5-8 OA 19-Nov-18 ALTTC/TX-I/DWDM

Optical Add/Drop Multiplexing Terminal Equipt In-Line Amplifier Terminal Equipt fixed OADM: 2 l1 l2 l2 Configurable OADM : 1 or 2 l1 l2 OADM : Optical Add/Drop Multiplexer 19-Nov-18 ALTTC/TX-I/DWDM

OADM Connectivity Omnibus From terminal to OADM, or from OADM to OADM 29 express ch 32 ch WDM Omnibus From terminal to OADM, or from OADM to OADM 19-Nov-18 ALTTC/TX-I/DWDM

DIFFERENCES FROM OLD SYSTEM REGs FIBRES REQUIREMENT LASERS TYPES OF COMPONENTS CAPACITY FIBRE TRANSMISSION BEHAVIOUR 19-Nov-18 ALTTC/TX-I/DWDM

ADVANTAGES OF DWDM 19-Nov-18 ALTTC/TX-I/DWDM

Why Optical (DWDM) Networking? Fibre Exhaust : Unlimited bandwidth on a fibre pair Bit Rate Transparency Format/Protocol Transparency : IP, ATM etc. Efficient use and rearrangement of embedded optical capacity as per demand. Minimal Capital Expenditure : Capacity Expansions Demand Simpler Operations : Embedded DCC 19-Nov-18 ALTTC/TX-I/DWDM

Economics of WDM Saving of regeneration costs: one optical amplifier for many channels regeneration cost per channel drastically reduced Saving of fibres/fibre shortage Cost effective compared to laying new fibres 19-Nov-18 ALTTC/TX-I/DWDM

DWDM Components Transmit Receive Repeater Add Drop Distribution: Cross connects 19-Nov-18 ALTTC/TX-I/DWDM

OPTICAL NETWORK ELEMENTS OADM OXC OMUX ODEMUX TP OA 19-Nov-18 ALTTC/TX-I/DWDM

TRANSPONDER / TRANSLATOR / WAVELENGTH CONVERTOR OPTIONAL REGENERATOR Electrical REGENERATION O/E E/O TRANSPONDER / TRANSLATOR / WAVELENGTH CONVERTOR 19-Nov-18 ALTTC/TX-I/DWDM

Optical Multiplexers & Filters W\L FILTER W\L MULTIPLEXER W\L ROUTER 19-Nov-18 ALTTC/TX-I/DWDM

OPTICAL ADD DROP MUX M D COUPLER CIRCULATOR 19-Nov-18 ALTTC/TX-I/DWDM

WAVELENGTH ADAPTATION OPTICAL CROSSCONNECT T SWITCH MATRIX T T T INPUT FIBRE LINKS OUTPUT FIBRE LINKS T T T T WAVELENGTH ADAPTATION TRIBUTARY LINKS 19-Nov-18 ALTTC/TX-I/DWDM

OPTICAL AMPLIFIERS Pump Pump laser laser Isolator Isolator Coupler Erbium-doped Fiber-(10-50 m) Pump laser Pump laser 19-Nov-18 ALTTC/TX-I/DWDM

NMS FOR DWDM SYSTEMS NMS IN CONVENTIONAL SDH SYSTEMS: DCC: TIME SLOTS DWDM – NO TIME SLOTS WAVELENGTH SLOTS ONE WAVELENGTH IS DEDICATED FOR N.M.S. OPTICAL SUPERVISORY CHANNEL OSC needs to be accessed at all points in the network 19-Nov-18 ALTTC/TX-I/DWDM

Line Terminal Equipment Optical Supervisory Channel (OSC) Line Terminal Equipment In-line Amplifier Tx 1 Tx 2 Tx 3 Tx 4 Tx 5 Tx 6 Tx 7 Tx 8 DATA IN 1 2 3 4 5 6 7 8 Rx DATA OUT Tx sup System Control Processor Rx Tx OSC System Control Processor Rx sup  + supervisory Network Management 19-Nov-18 ALTTC/TX-I/DWDM

OPTICAL BANDS EXTENSIVE USE OF WAVELENGTHS ITU Classification of bands DIFFERENT VENDORS:INTEROPERABILITY ISSUES NEED FOR STANDARD WAVELENGTH VALUES ITU Classification of bands Standard values : ITU Grid Center frequency: 193.10THz (1552.52 nm) Standard spacing of 200, 100, 50 GHz for different applications 19-Nov-18 ALTTC/TX-I/DWDM

C BAND PRODUCTS ARE COMMERCIALLY AVAILABLE. ITU-T BAND ALLOCATION C BAND L BAND Optical Supervisory channel BLUE BAND RED BAND 1500 1520 1530 1542 1547 1560 1620 C BAND PRODUCTS ARE COMMERCIALLY AVAILABLE. ERBIUM DOPED FIBRE AMPLIFIERS SUITABLE FOR ‘C’ BAND. GAIN IN RED BAND FLATTEST FOR EDFA. SOME MANUFACTURERS PROVIDE 16 CHANNELS IN RED BAND ONLY. OTHERS USE BOTH RED & BLUE BANDS. 19-Nov-18 ALTTC/TX-I/DWDM

ITU –T G.692 Frequency Grid Nominal Central  (THz) Central  (nm) 196.1 1528.77 194.7 1539.77 193.3 1550.92 196.0 1529.55 194.6 1540.56 193.2 1551.72 195.9 1530.33 194.5 1541.35 193.1 1552.52 195.8 1531.12 194.4 1542.14 193.0 1553.33 195.7 1531.90 194.3 1542.92 192.9 1554.13 195.6 1532.68 194.2 1543.73 192.8 1554.94 195.5 1533.47 194.1 1544.53 192.7 1555.75 195.4 1534.25 194.0 1545.32 192.6 1556.55 195.3 1535.04 193.9 1546.12 192.5 1557.36 195.2 1535.82 193.8 1546.92 192.4 1558.17 195.1 1536.61 193.7 1547.72 192.3 1558.98 195.0 1537.40 193.6 1548.51 192.2 1559.79 194.9 1538.19 193.5 1549.32 192.1 1560.61 194.8 193.4 1550.12 19-Nov-18 ALTTC/TX-I/DWDM

LIMITATIONS DWDM TRANSMISSION IS ANALOG. THE IN LINE AMPLIFIERS ARE ALSO ANALOG. THIS IMPLIES THAT THE SIGNAL TO NOISE RATIO WORSENS WITH DISTANCE. TO KEEP THE BER WITHIN LIMITS, THE SIGNALS ARE REQUIRED TO BE 3R PROCESSED IN ELECTRICAL DOMAIN. FIBRE DISPERSION IS ANOTHER LIMITATION. 19-Nov-18 ALTTC/TX-I/DWDM

LIMITATIONS THE MAXIMUM DISTANCE IS 640 Kms MADE OF 8 SPANS OF 80 Kms. THE ASSUMPTIONS ARE: * FIBRE ATT INCLUDING SPLICE LOSS IS 0.28 dB/km * SPAN LOSS OF 22 dB. * TOTAL DISPERSION IS LESS THAN 12800 ps/nm. 19-Nov-18 ALTTC/TX-I/DWDM

New Applications with DWDM Long Distance Longer Regenerator spacing: Hundreds to Thousands of Kilometers Saving of Regenerators Very Low Bandwidth Cost Scalability Very Fast Commissioning of Optical Paths: Within a week as compared to several months/ year with old technologies Advanced Networking Capabilities 19-Nov-18 ALTTC/TX-I/DWDM

New Applications with DWDM Metropolitan Area Network Unlimited Bandwidth, bit rate and format transparency Efficient Bandwidth use and Management 19-Nov-18 ALTTC/TX-I/DWDM

New Applications with DWDM High speed parallel Data Transport Certain Computer Applications Require that Computer Centers be interconnected with multiple high speed channels that have capacity and availability requirements, as well as interlink delay restrictions that can not be met by TDM Transport Systems. In General, DWDM Optical Transport Benefits all Delay Sensitive Applications 19-Nov-18 ALTTC/TX-I/DWDM

New Applications with DWDM Wavelength Leasing Network Customers are beginning to demand high capacity Network Transport that affords high reliability and security, as well as segmentations from the providers Network A spare Wavelength (Leased ) is used to provide clear-channel transport to a customer The Customer’s Bandwidth requirements are cleanly separated from the providers core Network Needs. 19-Nov-18 ALTTC/TX-I/DWDM

Thank You 19-Nov-18 ALTTC/TX-I/DWDM