Dense Wavelength Division Multiplexing Theory What we will

Dense Wavelength Division Multiplexing Theory

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

Background WDM TDM SDM

PDH, SDH and DWDM G. 692 DWDM G. 957 G. 691 SDH 155 M PDH 622 M 2. 5 G 10 G

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

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

DWDM Concept Dense wavelength division multiplexing (DWDM) Power (d. Bm) wavelength interval ： 0. 8～ 2 nm 1529 - 1560 nm λ(nm)

DWDM System Optical Transmitter Ch 1 ┇ OTUn λ 1 BA λs LA λs λs PA λs λn ODU Ch N λ 1 OMU Input OTU 1 Optical Receiver OLA ┇ λn OSC OSC EMS OTU 1 OTUn Ch 1 Output Ch N

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

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

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

Optical Add/Drop Multiplexer (OADM) • OADM performs add/drop of wavelengths Line side λ 1 λn Client side OADM

Operational Wavelength Range O Band Original 1260 -1360 nm E Band Extended 1360 -1460 nm S Band Short 1460 -1530 nm C Band Conventional 1530 -1565 nm L Band Long 1565 -1625 nm U Band Ultralong 1625 -1675 nm

Division Of Low-Loss Window

Feature Comparison between Low-Loss Window I II IV V Mark (nm) 850 1310 (O band) 1550 (C band) 1600 (L band) 1360 ~ 1530 (E + S bands) Wavelength range (nm) 600~900 1260~1360 1530~1565~1625 1360~1530 Fiber type 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

Wavelength Allocation On C-Band 40 Channels / 100 GHz interval No. Central Frequency (THz) Wavelength (nm) 1 192. 1 1560. 61 2 192. 2 1559. 79 3 192. 3 1558. 98 4 192. 4 1558. 17 5 192. 5 1557. 36 6 192. 6 1556. 55 7 192. 7 1555. 75 8 192. 8 1554. 94 9 192. 9 1554. 13 10 193. 0 1553. 33 11 193. 1 1552. 52 12 193. 2 1551. 72 13 193. 3 1550. 92 14 193. 4 1550. 12 15 193. 5 1549. 32 16 193. 6 1548. 51 17 193. 7 1547. 72 18 193. 8 1546. 92 19 193. 9 1546. 12 20 194. 0 1545. 32

Wavelength Allocation On C-Band 40 Channels / 100 GHz interval 21 194. 1 1544. 53 22 194. 2 1543. 73 23 194. 3 1542. 94 24 194. 4 1542. 14 25 194. 5 1541. 35 26 194. 6 1540. 56 27 194. 7 1539. 77 28 194. 8 1538. 98 29 194. 9 1538. 19 30 195. 0 1537. 40 31 195. 1 1536. 61 32 195. 2 1535. 82 33 195. 3 1535. 04 34 195. 4 1534. 25 35 195. 5 1533. 47 36 195. 6 1532. 68 37 195. 7 1531. 90 38 195. 8 1531. 12 39 195. 9 1530. 33 40 196. 0 1529. 55

DWDM vs. SDH • TDM • DWDM • Electrical Regenerator • Multi-wavelength on for Single Wavelength Single Fiber, for Optical Amplification Electrical Regenerator Transmitter l 1 T Electrical Multiplex l 1 l 2 l. N Receiver R Electrical Demultiplex l 1 l 2 l. N Optical Multiplexer l 1 l 2 OA l. N Optical Demultiplexer

DWDM Features Large transparent transmission capacity greatly saves fiber resources Each wavelength can carry different signal: SDH 2. 5 Gbps, 10 Gbps, ATM, IP DWDM technology provides multiple virtual fiber channels in one physical fiber channel SDH DWDM

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

DWDM Features 32*10 G 32*2. 5 G 16*2. 5 G 8*2. 5 G

Key technologies of DWDM

DWDM System Optical Transmitter Ch 1 ┇ OTUn λ 1 BA λs LA λs λs PA λs λn ODU Ch N λ 1 OMU Input OTU 1 Optical Receiver OLA ┇ λn OSC OSC EMS OTU 1 OTUn Ch 1 Output Ch N

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

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)

Optical Multiplexing and De-multiplexing Technology

Optical Multiplexer and Demultiplexer Multiplexer Demultiplexer Fiber

Supervision System Technology

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

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

Optical Supervision Control (OSC) OMU OBA OSC OLA OLA OPA OSC OSC ODU OMU OPA OLA OLA OBA

Optical Supervision Control (OSC) • • 1510 nm Signal speed : 2. 048 Mb/s Receiving sensitivity : -48 dbm Transmission power : 0 ~ -7 dbm

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