100-Gb/s Transport – A Reality Check TNC2010, Vilnius, May 2010 Dr. Klaus Grobe, Sr. Principal Engineer, ADVA Optical Networking, Advanced Technologies 100G Transport Techniques 2 © 2010 ADVA Optical Networking. All rights reserved. ADVA confidential. Modulation Formats ABC A transmitted signal s(t) can be described as: Ak A1 , A2 , ..., An , s(t ) Ak q(t kT ) Aj Aj e k q(t) – pulse shape, Ak – symbols containing the information RZ-OOK NRZ-OOK - + - 0 1 1 0 0 1 + 0 1 1 0 0 1 0 1 NRZ-DPSK CSRZ-OOK 1 0 0 1 + - + - - - + - 0 1 1 0 0 1 RZ-DPSK + - - - + - 0 1 1 0 0 1 PM-NRZ-DQPSK Phase-Shift Keying (phase modulation) Quaternary (4-state modulation) Differential (pre-coding) Non-Return-to-Zero (pulse shaping) Polarization-Multiplexed (a.k.a. Dual-Polarization, DP, a.k.a. Orthogonally-Polarized, OP) 3 © 2010 ADVA Optical Networking. All rights reserved. ADVA confidential. j j 100G constellation diagrams… Im QPSK Im Re 6PSK Im 8PSK Im 8QAM Re Re Re Various modulation schemes – PSK, QAM, … NRZ vs. RZ (duty cycle) Im Bipolar 6ASK Im Re Im 16PSK Re 4 9QAM Im DP-QPSK Re Im 16QAM Re Re Re Im 16QAM Im DP-8PSK Im DP-16QAM Re © 2010 ADVA Optical Networking. All rights reserved. ADVA confidential. Re Multi-carrier OSNR optimum for (DP-) QPSK (coherent) Cost-efficient 100G transport Different reach domains – 200 km vs. 2000 km Different requirements regarding protocol transparency, latency, spectral efficiency, … Leads to (at least) two different implementations, using different modulation at different cost points LH / Backbone, <2000 km SMF 1 x 112 Gb/s (28 GBd) Coherent PM-QPSK Enterprise, <200 km SMF 4 x 28 Gb/s DWDM / SCM Different solutions at different cost points! 5 © 2010 ADVA Optical Networking. All rights reserved. ADVA confidential. Cost-optimized 100G Transport 6 © 2010 ADVA Optical Networking. All rights reserved. ADVA confidential. High-speed Transport Roadmap 40G & 100G Transport Cards in FSP 3000 100G: LH 100G Carrier Core 40G: 1st Gen. 40G: Highly-Tolerant 40G Carrier Core 100G: Enterprise 100G Enterprise 2009 7 2010 2011 © 2010 ADVA Optical Networking. All rights reserved. ADVA confidential. 2012 90° QPSK Coder Driver Filter PBS LO PC 90° 90° Hybr. 0° Client I/F (CFP) PBC 90° FEC, Framing, Monitoring PC PBS PC Digital Filter (FFE) CW LD 0° ADC 90° 90° Hybr. ADC Driver Filter ADC FEC, Framing, Monitoring Client I/F (CFP) QPSK Coder ADC 112G Coherent PolMux-QPSK Im PM-QPSK Highest performance 100G transport, but highest complexity (cost) Supports 50 GHz DWDM with 28 GBd and 2 (bit/s)/Hz spectral efficiency, ROADM networking, and 1500…2000 km reach Digital filter for 4x28 Gb/s (necessary for Polarization demultiplexing, dispersion compensation, etc.) not yet available ADVA is part of Georgia Tech consortium which follows PM-QPSK 8 © 2010 ADVA Optical Networking. All rights reserved. ADVA confidential. Re ADVA Tests on PM-DQPSK w/ WSS Transmitted over ~540 km (6 spans) with Wavelength-Selective Switches OSNR: 22.6 dB WSS, EDFAs and DCMs from current ADVA product line 90° 28 GHz Clock 6X PC WSS PC EDFA 90 km SSMF EDFA PBS PC 28 Gb/s Data B DCM Y Polarization (Q) (I) Q = 3.83 9 (I) Q =3.48 R T- R WSS PBS X Polarization T+ BERT 28 Gb/s Data A CW (Q) Q = 3.09 © 2010 ADVA Optical Networking. All rights reserved. ADVA confidential. Q =3.24 Carrier Core Trans/Muxponder High-performance network interface Im PM-QPSK PM-QPSK with coherent detection (OIF standard) 50 GHz channel spacing Re Long-Haul capability >1500 km reach Dispersion (CD, PMD) compensation Strong FEC G.709-compliant mapping, multiplexing Services 100GbE (IEEE802.3ba), OTU4 (G.709) 10 x 10GbE / STM-64 / OC-192 4 Slots 10 4 Slots © 2010 ADVA Optical Networking. All rights reserved. ADVA confidential. Low-Cost / Data Center 100G Transport Application areas Why latency matters Storage/SAN connectivity Reasons for (differential) latency LAN/HPC/Cloud connectivity Link Group Delay, 100 km round-trip = 1 ms 10GbE metro transport Multiplexing, mapping, framing, typ. <100 µs FEC, up to 100 µs, differential delay! Client protocols 10x10GbE, native 100GbE High-end requirements 12x8G-FC, 6x16G-FC Total delay, e.g., clustering, <10…100 µs Differential delay, e.g., GDPS, <500 ns IB QDRx8, EDRx4 Distance often <100 km Low latency Counter-actions Low-latency design Avoid FEC Benchmark Short links Cost of 10 x 10G DWDM T-XFPs 2.5 x total system capacity compared to T-XFPs @ 50 GHz 11 © 2010 ADVA Optical Networking. All rights reserved. ADVA confidential. Rx Rx Rx Multi-Carrier Modulation - 4 directly modulated lasers (DML) 4x28G, spectral efficiency 0.5…1 (bit/s)/Hz Low power consumption, very small footprint Low latency design, optional FEC bypass ()3 Optical Client I/F + 4 x ODB Coders DMX R + DMX ~ R R R Optical Client I/F Proof of concept of 4x25G transmission in 100GHz [K. Yonenaga et.al., JThA48, OFC/NFOEC 2008] 12 © 2010 ADVA Optical Networking. All rights reserved. ADVA confidential. Client I/F Rx FEC Filter/Splitter DML ITU-T DWDM DML ITU-T DWDM DML 4:1 Coupler DML FEC Client I/F Low-cost 100G Data Center Transport 100G Enterprise Muxponder 10TCE-PCN-10GU+100G Low-cost network interface design DML with enhanced dispersion tolerance Pluggable optics Clients: Multi-rate SFP+ 850/1310nm Network: based on CFP CFP 4 x 28 Gb/s DWDM 4 x 28 Gb/s DWDM multi-carriers Record compactness 2-slot card SFP+ 800 Gb/s per shelf 2 Tb/s per 80 channels / 50GHz 6.4 Tb/s per ETSI footprint Complemented by 100GbE transponder (WCE-PCN-100G) 13 © 2010 ADVA Optical Networking. All rights reserved. ADVA confidential. Implementation and Variants Client Interface Module 14 MDIO Main Board Quad Laser Driver DML DML DML DML Quad PIN-TIA CAUI 4:10 Gearbox IC FCE Skew Mgmt. SFP+ Line OAM/ECC … 1:10 Mux SFP+ Rate Adapt. SFP+ MLD/PCS Mon. 10x11.18G 4:10 Gearbox IC Power Supply MDIO/Ctrl. Pluggable © 2010 ADVA Optical Networking. All rights reserved. ADVA confidential. 25 GHz Variants 25 GHz WDM Grid 100 GHz WDM Grid (SCM) DML 25G-locked DML 25G-locked Power [dB] DML MX DML 100 GHz DWDM -20 -40 -60 1 DX DML Quad Laser Driver DML DML DP-QPSK DML Quad PIN-TIA DML Quad PIN-TIA Quad Laser Driver 0 P Optics Module Alternatively, 4x28G-to-100-GHz optics for Sub-Carrier Multiplexing © 2010 ADVA Optical Networking. All rights reserved. ADVA confidential. 1 Normalized Frequency Filtered DML can directly support 25-GHz DWDM grid 15 0 100G Solution Comparison 16 100G Enterprise 100G Long-haul Single/multi-Carrier 4 x 28 Gb/s DWDM (SCM) Single Carrier Modulation NRZ Filtered DML with Direct Detection NRZ-DP-QPSK with Coherent Intradyne Detection + DSP Spectral efficiency [b/s/Hz] C-Band Capacity [Tb/s] 0.5…1.0 2…4 2 8 OSNR [dB], Reach [km] 22 dB w/ FEC, 28 dB SCM w/ FEC, 28 dB w/o FEC, 34 dB SCM w/o FEC, CD Tolerance [ps/nm] Mean PMD Tolerance [ps] -250...+500 w/o TDC 5 @ 1 dB OSNR Penalty >40,000 (FFE) >30 (FFE) Size (slots) Power consumption [W] 2 95 4 120 Target Cost [relative] 50% 100% 600 km 200 km 200 km 50 km 15 dB, >1,500 km © 2010 ADVA Optical Networking. All rights reserved. ADVA confidential. Conclusion Cost-optimized 100G transport needs differentiated solutions, depending on applications’ reach (and spectral eff.) needs Data center / HPC also require low latency Mixture of high-performance Coherent DP-QPSK and low-cost, latency-optimized Multi-Carrier Modulation Mix of two solutions does not cause significant OpEx mark-up, but reduces CapEx significantly for DC/HPC/access applications 100G deployment can start with low-cost variant, moving these transport cards to less-utilized links later 17 © 2010 ADVA Optical Networking. All rights reserved. ADVA confidential. Thank you [email protected] IMPORTANT NOTICE The content of this presentation is strictly confidential. ADVA Optical Networking is the exclusive owner or licensee of the content, material, and information in this presentation. Any reproduction, publication or reprint, in whole or in part, is strictly prohibited. The information in this presentation may not be accurate, complete or up to date, and is provided without warranties or representations of any kind, either express or implied. ADVA Optical Networking shall not be responsible for and disclaims any liability for any loss or damages, including without limitation, direct, indirect, incidental, consequential and special damages, alleged to have been caused by or in connection with using and/or relying on the information contained in this presentation. Copyright © for the entire content of this presentation: ADVA Optical Networking. 18 © 2010 ADVA Optical Networking. All rights reserved. ADVA confidential.