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광통신 : Evolution to Next Step

광통신 : Evolution to Next Step. Chang-Hee Lee (chl @ ee.kaist.ac.kr) Korea Advanced Institute of Science and Technology 2003.4.11. Access ring OC48/GbE. CO. OC3. Metro Core C/DWDM OC48/192. POP. Access ring OC48/GbE. Long-haul DWDM OC48/192/768. CO. Metro Core C/DWDM OC48/192.

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광통신 : Evolution to Next Step

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  1. 광통신 : Evolution to Next Step Chang-Hee Lee (chl@ee.kaist.ac.kr) Korea Advanced Institute of Science and Technology 2003.4.11

  2. Access ring OC48/GbE CO OC3 Metro Core C/DWDM OC48/192 POP Access ring OC48/GbE Long-haul DWDM OC48/192/768 CO Metro Core C/DWDM OC48/192 POP T1 CO POP CO PON Business CO CO PON POP Access ring OC48/GbE GbEs Metro Core C/DWDM OC48/192 Residential GbE Business Residential CO Access ring OC48/GbE CO Access ring OC48/GbE Optical Networks

  3. * Lightwave 98/4, M. Shariff, Cisco systems Inc. % Voice 100 50 Data 1 1996 1997 1998 1999 2000 2001 Traffic Growth • Slow growth for Voice • Exponential growth for data • # of subscriber * data size * connection time • Not exponential in Korea • High capacity WDM networks were required to meet demands. • However, there is big mismatch between expectation and reality (factor of 8 ~ 10). • Revenue growth is slow.

  4. Recovery Scenarios (Optical Components)

  5. OXC Interconnected rings and mesh topologies OXC OXC OXC OXC WDM Rings with full connectivity WDM Rings with node addressing WDM transmission with Add/Drop WDM transmission OADM WDM Backbone Network Evolution(delayed due to down turn) Technology Evolution “Road map towards the optical communication” 1998, 5, ACTS 1996 1998 2000 2002 1996 1998 2002/3 2005/6

  6. Huge bandwidth in backbone due to cost effective DWDM technology Huge investment, but small revenue Restructuring carriers and vendors Many big players with relatively small growth How many carriers and vendors will survive? Carriers and vendors are looking for next generation systems/networks Mesh networks based on 10 Gb/s or 40 Gb/s ultra-long reach Backbone Networks(North America case)

  7. Spectral efficiency 40 Gb/s or higher Bidirectional transmission Modulation format(duobinary …) Polarization mux. Wide bandwidth L-band S-band New band Long reach Dynamic gain flattening Raman/hybrid Modulation format(CS-RZ, RZ) Dispersion and PMD management FEC High capacity WDM systems

  8. Raman amplifier FEC(Forward Error Correction) Dynamic gain flattening Dynamic dispersion compensation PDM compensation All optical regeneration (3 R) Optimization of modulation format Key Technologies(long reach systems)

  9. 1.2 lp=1mm 1.0 0.8 RAMAN GAIN (x10-13 m/W) 0.6 0.4 0.2 0 0 6 24 12 18 30 36 42 FREQUENCY SHIFT (THz) Raman Gain Spectrum

  10. Pump source with Raman Raman amplifier increase input power to EDFA or to detector Raman Amplifiers Transmission fiber Pout Pin’ without Raman Pin

  11. 1 2 3 4 Though Traffic & Dropped Traffic(connection of many nodes) • Total traffic in link for • full-mesh connectivity • . Node-to-node traffic * N (N-1) / 2 • Dropped traffic • . Node-to-node traffic * (N-1) • Dropping ratio • = 2 / N N Ring topology N-1 Add/drop multiplexing of bundle of circuits(path) at each node

  12. Electrical path networks Optical path networks Path termination nodes OADM All nodes n x SDH 16 or 64 n x SDH 16 or 64 SDH 16 or 64 SDH 16 or 64 LT MUX . . . . ADM/DCS SDH 16 or 64 Terminations of a portion of line capacity and cross-connection SDH 16 or 64 MUX/DMUX OE/EO LT MUX Path through nodes ADM/DCS Terminations of total line capacity and its cross-connection OADM n x SDH 16 or 64 n x SDH 16 or 64 Evolution of Path Networks

  13. Protection ADM ADM ULSR UPSR Switch Working Working Protection ADM ADM BLSR/2(bi) BLSR/4 Working Working Protection Protection 2 working + 2 protection fiber 1 working + 1 protection fiber Protection in ring networks

  14. Working S w I t c h S w I t c h Working S w I t c h S w I t c h W D M W D M W D M W D M W D M W D M Protection Working S w I t c h S w I t c h Protection Protection ADMs Unidirectional Ring ADMs Bidirectional Ring(4-f) Unidirectional Ring vs. Bidirectional Ring

  15. Mesh Networks Cross connect Restoration path Fiber cut Normal operation • High capacity survivable network • High degree of wavelength reusability

  16. Electrical path networks All nodes DMUX MUX . . . . . . SDH 16 or 64 SDH 16 or 64 . . . . SDH 16 or 64 SDH 16 or 64 DMUX MUX . . . . . . MUX/DMUX OE/EO LT MUX ADM/DCS DMUX MUX . . . . . . Electrical Path Controller 10Gb/s 10Gb/s VC-3 or VC-4 STM-64 STM-64 VC-3 or VC-4 VC-n Cross-connect matrix 2.5Gb/s 2.5Gb/s STM-16 STM-16 155Mb/s 155Mb/s STM-1 STM-1 VC-1/VC-3 VC-1/VC-3 Terminations of total line capacity and its cross-connection

  17. Control Circuit Optical Cross-connect System Input Output l1 l1 l1, l2, ... ln l1, l2, ... ln W D W M 1 . . . . . . . . 1 ln n x STM 64 n x STM 64 W D W M . . . . . . . . 2 2 n x STM 16 n x STM 16 ln W D W M . . . . . . . . m m Drop signal Add signal Space switch(n x n)

  18. Path-oriented WDM Optical and Data Networks WDM optical networks utilize physical paths Data networks utilize logical paths Create associations logical and physical paths Enables mgmt of optical I/F and mgmt services Evolution of Optical Path IP IP IP ATM Intelligent Layer Internetworking IP ATM SONET/SDH SONET/SDH Improved efficiency and control WDM Optical Network Source : OIF

  19. Bottleneck in Metro/Access 20 Mb/s Equivalent BW/subscribers 1 Mb/s 64 kb/s Subscriber Access Metro Backbone

  20. Backbone network Rich of bandwidth; DWDM (100 Gb/s ~ multi Tb/s) SONET, RPR, POS, MPLS, .. Metro-core Establishing bandwidth rapidly; C/DWDM(2.5 Gb/s ~ 100 Gb/s) SONET, RPR, POS, MPLS, Ethernet… Access Copper based network; 100 kb/s ~ Mb/s depends on distance However, SME requires up to Gb/s services and advanced home more than 20 Mb/s. ADSL, VDSL, Ethernet, ATM, …. Bottleneck Moves to Access

  21. Bandwidth Demands and Subscriber Estimation Bandwidth demands Subscribers in Korea Business subscribers require about ~ Gb/s services Source: Ministry of Information and Communication(MIC)

  22. WDM-PON 52 30 26 E-PON (w/ 32 ONU) VDSL 8 6 3 Access Solutions 1000 100 Bit Rate [Mb/s] 10 ADSL 1 20 3 5 1 2 4 6 Distance [km] • Source: ITU-T

  23. 25 Plan Fiber solutions FTTH 20 15 Fiber solutions FTTC Subscriber speed [Mb/s] 10 Result 5 Copper solution 1.6 Mb/s 1.0 Mb/s 0 1999 2001 2003 2005 Year Why Fiber Solution ? • - Copper based solution cannot provide broadband services. • - TDM-PON cannot meet long-term bandwidth requirement. • - WDM-PON is the only solution for next generation • Broadband access. Source; MIC

  24. Physical topology P-t-P, P-t-MP P-t-MP solutions; Ring, Single star, Double star Passive vs. active networks Multiple access methods TDMA, WDMA, SCMA, CDMA Access and communication protocol; ATM, Ethernet, SONET, … Costs Initial deployment cost  Equipment cost Provisioning and maintenance costs Upgrade cost General Considerations on(Optical Solutions)

  25. N (or 2N) fibers 2N transceivers High fibers and management cost High cost ONU # 1 ONU # 2 CO ONU # 3 ONU # 4 ONU # N ONU #… Access network Architectures(P-t-P)

  26. 2 Passive remote node Active remote 2 3 4 3 time Passive optical power splitter 4 Access Network Architectures(P-t-MP) ONU #1 ONU #2 ONU #4 CO ONU #5 ONU #N

  27. l 1 1 2 2 3 3 4 4 5 5 l Passive optical power splitter 1 2 3 4 5 Access Network Architectures(P-t-MP) ONU #1 ONU #2 ONU #4 CO ONU #5 ONU #N

  28. P-t-MP(S) P-t-MP(R) Architecture Access method Protocol transparency Security Offered BW Transmission  Link budget > Gb/s possibility Cost P-t-P None Yes High Unlimited Any  Highest Yes High (Fiber cost) TDMA No Low Limited Any  Low No Low WDMA Yes Low Limited Fixed  Lowest Limited Medium (Source cost) WDMA Yes High Unlimited Fixed * High Yes Medium (Source cost) Comparison of PONs * If router has high temperature dependency, it may need tunable sources.

  29. Basic principles of optical communication were reviewed. - Optical transmitter - Optical receiver - Optical amplifier - Wavelength division multiplexing - Optical networking Optical communication/network is essential for future information highway Summary

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