A System's View of Metro and Regional Optical Networks

Cedric F. Lam ( [email_address] ) and Winston I. Way ( [email_address] ) SPIE Photonics West, Jan 29, 2009, San Jose, CA A System’s View of Metro and Regional Optical Networks

Outline ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

Growing Broadband Applications and Technologies IPTV Nomadic Device Tele-presence Network Gaming Wi-Max xPON Backbone networks have to scale simultaneously!

Broadband Access http://www.ieee802.org/3/hssg/public/nov07/HSSG_Tutorial_1107.zip Source: IEEE 802.3 HSSG Tutorial Internet and IPTV dominate bandwidth

Information Capacity – the Shannon Limit ,[object Object],[object Object],[object Object],[object Object],[object Object],Information Capacity (bits/s) Bandwidth Signal-to-Noise Ratio Ref: C.Shannon, Bell Systems Technical J., Vol.27, p.379 (1948)

A Signal Constellation View ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],I Q noise conditional signal probability 0000 0100 a /2 I Q M-QAM signal constellation 1100 1000 0001 0101 1101 1001 1011 1111 0111 0011 0010 0110 1110 1010  d

Modulation Formats - View from Constellation Diagrams ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],0000 0100 a /2 I Q I Q I Q I Q (a) OOK (b) BPSK (c) QPSK (d) 16-QAM 0 1 1 0 00 10 11 01 1100 1000 0001 0101 1101 1001 1011 1111 0111 0011 0010 0110 1110 1010 Function of modulation format

Self Coherent Modulation ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],Coherent BPSK Receiver DPSK Receiver PC Rx LO CDR CDR Rx 1-bit delay

Complexity vs. Benefits Pre-coded Data CDR Rx Modulation Transmitter Receiver OSNR (dB) @ 1e-3 , 42.7G NRZ-OOK NRZ-DPSK NRZ- DQPSK (no pol-mux) 16 dB 1 bit/symbol 14 dB 1 bit/symbol 15 dB 2 bits/symbol LD Data LD Pre-coded data-I LD Pre-coded Data-Q  /2 CDR Rx 1-symbol delay  CDR  I-branch data Q-branch data CDR Rx 1-bit delay

Spectral Efficiency – Where Are We Today? M. Nakazawa: ECOC 2008 paper Tu.1.E.1 C-band: W=4THz , OSNR = 16dB (P/N=14.1dB @40Gb/s) Total Capacity (b/s) Spectral Efficiency (b/s/Hz) Shannon Limit 18.8T 4.7 Commercial Systems 10G x 40  (100GHz spacing) 400 G 0.1 10G x 80  (50GHz spacing) 800 G 0.2 40G x 40  (100GHz spacing) 1.6 T 0.4 40G x 80  (50GHz spacing) 3.2 T 0.8

EDFA C-band (Bandwidth = 4 THz) Utilization To support 50GHz spaced 100GE, we need to achieve C/W = 2 (b/s)/Hz 4x 100GbE 10G,100GHz space 10G, 50GHz space 10G, 12.5GHz space 8x 100GbE 32x 100GbE (125GHz space) C-band Gain + lowest fiber loss Maximizes P/N in Shannon capacity 80 x 100GbE (50GHz space) Commercially achieved

Metro / Regional WDM Network Architecture Metro/Regional WDM Transport Backbone PON LAN Wi-Max or LTE EDFA DCM ROADM DCM TRX TRX TRX

Typical Optical Layer Characteristics ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

Challenges to Upgrade to 40Gb/s & 100Gb/s per Lambda ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],For the same modulation format NRZ-OOK Bit Rate (b/s) Residual Dispersion Equivalent SMF Length 2.5G 10880 ps/nm 640 km 10G 680 ps/nm 40 km 40G 42.5 ps/nm 2.5 km 100G 6.8 ps/nm 0.4 km NRZ-OOK Bit Rate (b/s) Mean DGD @ 1dB OSNR Penalty (ps) 10G 11 40G 2.7

Upgrade Strategies ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],Cost effectiveness and compatibility with legacy 10Gb/s infrastructure is very important, especially in today’s tough economy!

DSP Based Coherent Receiver with Polarization Multiplexing ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],0    90 - degree hybrid A/D A/D 0    90 - degree hybrid A/D A/D Rx / Tx DSP F EC X Y PBC 90 o CW X-Pol I X-Pol Q Y-Pol I Y-Pol Q DPMZ Modulators Hi-speed ASIC 90 o LO

Non-linearity in PM-QPSK Oriol Bertran Pardo et. al: “Investigation of design options for overlaying 40Gb/s coherent PDM-QPSK channels over a 10Gb/s system infrastructure,” OFC 2008, paper OTuM 5 Performance significantly affected by XPM induced by neighboring 10G NRZ OOK signals.

10-Gbaud Dense Multi-Carrier Technology ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],10Gbaud Dense Multicarrier Technology 40G (4x10G) 100G (5x20G) 100GHz 100GHz or 50GHz-spaced 100GHz-spaced 40G (2x20G) 50GHz 50GHz-spaced 50GHz

Cost Ratio Comparison of 40G/10G Technologies Source: H. Bosco, “Network Evolution to 40Gb/s”, ECOC 2008 Cost of 40G interface is significantly higher than that of 4x10G! DMC 40G DMC 100G OpNext Estimate

40Gb/s Line Side Modulation Scheme Comparison DMC – 4x10G DMC – 2x20G PSBT (ODB) NRZ-DPSK RZ-DQPSK PM-QPSK Relative Cost Estimate -20% -10% 0% +20% +60% +75% CD Tolerance (ps/nm) 2000 500 320 100 200 35000 PMD Tolerance (ps) 10 (17) 10 2.1 2.5 8 30 OSNR Sensitivity (dB) 16.5 13.5 17.5 14 15 11 XPM Tolerance from 10G High High High High Low Low Applications Upgrade any 10G infra-structure + Greenfield Upgrade any 10G infra-structure + Greenfield Green Field Green Field Green Field Upgrade any 2.5G/10G infrastructure without 10G NRZ neighbors

Pay-as-you grow 100-G product Version 1 Demonstrated at NXTCOMM 2008 Version 2 Q1/2009 100G (5x20G) 40G (2x20G) 20G Module 2RU 19” CX-100G

DMC 40G/100G + NRZ 10G transmission through 1000km SMF-28 100G 40G 40G 10G 10G 10G 10G 10G 10G 10G

4x10G DMC Lab/Field Trials in 2008 Lab#1 Lab#2 Lab#3 Field#1 Field#2 Field#3 Reach 975km SMF-28 1910km SMF-28 565km SMF-28 130km SMF-28 860km G.655 752km G.652 #spans, span distance 13x75km 80kmx25 7 spans, 50-105km 1 span 12 spans, 10-90km 50-100km span OSNR @BER=1e-3 16.5 dB 16.7 dB after 1601km 16.4 dB 17.1 dB after 752km PMD Tolerance 9 ps (1dB Q) 10 ps (1dB OSNR) CD Tolerance -135km ~ +160km SMF-28 -2500 ~ +1750 ps/nm -2500 ~ +1750 ps/nm Filtering Tolerance 100GHz DWDM Mux/demux 2x 100/50GHz inter-leavers 4 WSS 100GHz DWDM Mux/demux 25GHz OAD 0.5-dB BW 200GHz DWDM mux/demux Fiber Nonlinearity Tolerance +6 dBm/ch +0 dBm/ch +6 dBm/ch > +4 dBm/ch > +4 dBm/ch #10G OOK neighbors 39 14 2 2 3 12

Optical Spectrum of 39x10G NRZ + DMC 1x40G OpVista’s 40G DMC 975km SMF-28

40G DMC through 975km SMF-28 with 39x10G Signals #1 #2 #8 #14 Error-free transmission for 37 hours With DCF

Received spectra for a 1750 km (23 spans) customer lab test ,[object Object],-4dBm launch power

1750 km (23 SPANS), Four-wave Mixing Test ,[object Object],[object Object],[object Object],Received spectrum for launch power 6 dB above the nominal (2 dBm/ch) Received spectrum for nominal launch power (-4 dBm/ch)

Best-of-class Non-linearity Tolerance FEC Limit 4x 10G DMC Performance Q or OSNR (dB)

Transparent Network Backbone ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

Scalable ROADM Principle ,[object Object],[object Object],[object Object], 2 T R X T R X  1  2  1 JAD Protection Span Clients Clients Working Path Node 1 Node 2 Node 3 Node 4 Node 5 Protection Path Protection Couplers

Protection Switching  2 T R X T R X  1  2  1 JAD Protection Span Clients Clients Working Path Node 1 Node 2 Node 3 Node 4 Node 5 Protection Path Protection Couplers

Scalable ROADM Network Interface TRX: transceiver JAD: Junction add/drop (a) System Diagram (b) JAD Cards

Scalable ROADM Node Add/Drops ,[object Object],[object Object],[object Object],Line Out Line In PD Line In Line Out PD 1:n 1:n Ea st We st Tx Rx WB WB OSC T R T R

Field Tested Technology OFC/NFOEC 2009 Paper JWA86

Conclusion ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

A System's View of Metro and Regional Optical Networks

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A System's View of Metro and Regional Optical Networks