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SCALING OPTICAL NETWORKS WITH ADVANCED PHOTONICS Ove Parmlind with acknowledgement to David Butler 1 © Nokia 2016 Nokia Public Use AGENDA 1. How on earth did we get here? 2. An insatiable appetite…………. Tutorial 3. Our desires 4. What stops us 5. Squeezing out the last drop 6. Packing them in Technology for Scalable Networks 7. The other piece 8. Tools to maintain performance 2 © Nokia 2016 Nokia Public Use An Insatiable Appetite [Stolen from P. J. Winzer, Bell Labs Tech. J., 2014] 20% TO 90% GROWTH PER YEAR, WIDELY DEPENDENT ON MARKET SEGMENT, OPERATOR, AND GEOGRAPHY 3 © Nokia 2016 Nokia Public Use Heart Attack Grill® Quadruple Bypass Burger® AN INSATIABLE APPETITE Global Internet Traffic Forecast 200 180 Exabytes per Month 160 140 120 100 80 60 23% CAGR 2014-2019 40 0.9dB/year 20 0 2013 © Nokia 2016 2015 2016 2017 2018 2019 2020 Cisco VNI Global IP Traffic Forecast, 2014-2019 Heart Attack Grill® 4 2014 Nokia Public Use Demand Supply 2014 2019 2025? 0.9 dB/year Long Haul WDM Platform Capacity WDM Capacity Tb/s per Fibre 100 0.8dB/year 0.25dB/year 3.1dB/year 10 Metro 60EB/Month* 168EB/Month* Spectral Efficiency of 4 bit/s/Hz 1 Spectral Efficiency of 1 bit/s/Hz 0.1 0.6 dB/year 0.01 1990 1995 2000 2005 2010 2015 2020 2025 2030 2035 Long Haul 29EB/Month* 57EB/Month* * Cisco VNI Global IP Traffic Forecast, 2014-2019 5 © Nokia 2016 Nokia Public Use OUR DESIRES Capacity Reach Power Joshua Heller CC BY-SA 2.0 Low Cost 6 © Nokia 2016 Size Nokia Public Use Flexible WHAT STOPS US 7 © Nokia 2016 Nokia Public Use PULSE PROPAGATION Receiver Transmitter A i 1 2 A 2 i A 2 A A0 z 2 2 dT 2 © Robertson. Smithsonian Institution United States 8 © Nokia 2016 Nokia Public Use PULSE PROPAGATION A i 1 2 A 2 i A 2 A A0 z 2 2 dT 2 Losses – predominantly in the fibre overcome with amplifiers generating noise Chromatic Dispersion historically overcome with in line compensation Nonlinear effects Additionally time varying penalties, such as Polarization Mode Dispersion, need to be considered 9 © Nokia 2016 Nokia Public Use NOISE Generally dominated by Amplified Spontaneous Emission Added by each amplifier in the line Noise power is proportional to the gain required Noise is conventionally given in terms of Optical Signal to Noise Ratio (OSNR) measured in 0.1nm (although one vendor uses 0.5nm!) For a line system delivering a high OSNR is good For a receiver tolerating a low OSNR is good 10 © Nokia 2016 Nokia Public Use Bob Mellish CC BY-SA 3.0 CHROMATIC DISPERSION Demonstration of error-free 25Gb/s duobinary transmission using a colourless reflective integrated modulator; Caroline P Lai et al.; Optics Express Vol.21, Issue 1 11 © Nokia 2016 Nokia Public Use Nonlinearity JOHN KERR Who is to blame? Change in refractive index is proportional to the SQUARE of the electric field Public Domain 12 © Nokia 2016 Nokia Public Use NONLINEARITY Self-phase modulation (SPM) Cross-phase modulation (XPM) A single-channel effect A multi-channel effect 2 dBm 17 dBm Ps = 2 dBm 18 dBm Pc = 13 dBm 20 dBm Intensity distortion after single-channel propagation in a 2x80km link (for different channel powers) 13 © Nokia 2016 Nokia Public Use Intensity distortion after two-channel propagation in a 2x80km link Nonlinearity Four-wave mixing (FWM) Stimulated Raman Scattering (SRS) A multi-channel effect A multi-channel effect Generation of intermodulation frequency components at f = fi + fj - fk Energy transfer from lower-wavelength to higherwavelength channels It generates an extra tilt, which is taken into account in the link design 14 © Nokia 2016 Nokia Public Use Power (0.5dB/Div) Power (0.5 dB/Div) Experimental spectrum recorded after 25km of G.653 fibre with 3 channels at unequal spacing 2.3 dB Fibre output (5.6 dBm/ch) Fibre input POLARIZATION MODE DISPERSION (PMD) PMD is due to the asymmetry of the fiber strand. This can be caused by intrinsic geometric imperfections or by the cabling putting stress around onto the core. The birefringence in the optical fiber slows down the X-polarized state that sees the higher refractive index and causes a differential group delay (DGD) between the polarization states resulting in pulse distortion p 1.0E+00 1.0E–01 The probability of exceeding 3.2 times the mean DGD is around 1E-05 which corresponds to about 5 min/year 1.0E–02 1.0E–03 1.0E–04 1.0E–05 p 1.0E–06 1.0E–07 1.0E–08 1.0E–09 1.0E–10 0 < > 2 < > 3 < > T1540440-00 DGD Probability Distribution Function Average DGD (PMD) 15 © Nokia 2016 Nokia Public Use “40Gb/s Networks and the PMD Challenge” ;richard.ednay & modesto.morais POLARIZATION MODE DISPERSION (PMD) 16 © Nokia 2016 Nokia Public Use PMD Reach 10Gb/s 100Gb/s (ps/√km) (km) (km) 0.2 0.5 1 2 5 2500 400 100 25 4 >10 000 >10 000 10 000 2500 400 NETWORK AUTOMATION DESIGN, DEPLOYMENT & MANAGEMENT • Network design and planning tools • Integrated with Network Management 17 © Nokia 2016 Nokia Public Use THE CHOICE OF FIBRE Srleffler licensed under CC BY-SA 3.0 Typical Zero Dispersion Dispersio Effective Fibre Type @1550nm Wavelen (µm2) (ps/nm(nm) EX2000 18 © Nokia 2016 Nokia Public Use 20 1310 112 Excellent loss & non-linear tolerance. G.652 17.1 1310 80 Very good non-linear performance Teralight 6.5 1425 63 Probably the best performing G.655 fibre TrueWave-RS 4.6 1446 56 Poor XPM in blue end primarily due to LEAF 4.1 1511 73 Poor XPM in blue end primarily due to TrueWave 3.5 1496 59 Poor XPM in blue end primarily due to G.653 0.1 1549 48 Very poor non-linear performance LS -1.6 1571 56 Poor nonlinear performance particularly SQUEEZING OUT THE LAST DROP 19 © Nokia 2016 Nokia Public Use THE TOOLSET TO MEET NETWORK TRAFFIC GROWTH FIVE PHYSICAL DIMENSIONS OF AN ELECTRO-MAGNETIC WAVE Polarization Space Waveforms change in … Time • Frequency Amplitude & Phase Same 5 physical dimensions across all communications technologies (Wireless, DSL, Optics, …) ORDER OF DEPLOYMENT MATTERS – HIGHLY APPLICATION SPECIFIC Stolen from Peter Winzer 20 © Nokia 2016 Nokia Public Use MANY MANY MOONS AGO…….. TIME AND AMPLITUDE Polarization Space Time Public Domain 21 © Nokia 2016 Nokia Public Use Frequency Amplitude & Phase BEFORE “THE INTERNET” WAS CALLED “THE INTERNET” ADD COLOUR 1993 1987 Polarization Space Time 1991 22 © Nokia 2016 Nokia Public Use Frequency Amplitude & Phase BEFORE FACEBOOK ADD PHASE Polarization Frequency Space Time Amplitude & Phase -1 0 1 Duobinary Made 40Gb/s per carrier possible 23 © Nokia 2016 Nokia Public Use 0 1 1 1 0 0 1 0 DQPSK & with Polarization Multiplexing............ Increasing Implementation Complexity PDM-BPSK PDM-QPSK PDM16QAM PDM64QAM 2 bits/symbol 4 bits/symbol 8 bits/symbol 12 bits/symbol Spectral efficiency comes at a cost: Higher signal-to-noise ratio (SNR) requirements for higher-order modulation 24 © Nokia 2016 Nokia Public Use 45 GBAUD (90GS/S) OPERATION BECAME FEASIBLE @ 28NM CMOS 200Gb/s Options 40nm CMOS 32 GBaud PDM-16QAM 28nm DAC with 45 GBaud and Gaussian shaping 25 © Nokia 2016 Nokia Public Use 28nm CMOS 43 GBaud “PDM-8QAM” FLEXIBLE CHANNEL RATES NEW FORMATS • 64QAM offering maximum capacity on short distances NEW 100G HI-PERFORMANCE SP-QPSK • 8QAM well suited for long haul 200G applications 100G QPSK NEW 200G HI-PERFORMANCE REAC H 8QAM • SP-QPSK for maximum 100G reach in a single-carrier solution 200G 16QAM NEW 400G HI-CAPACITY EXAMPLE REACHES SP-QPSK – 5000 km 64QAM CAPACITY 26 © Nokia 2016 Nokia Public Use QPSK – 3000 km “8QAM” – 1500 km 16QAM – 600 km 64QAM – 150 km Q² factor [dB] WHY 200GB/S 8QAM? Theory PDMQPSK PDM-QPSK (direct enc./dec.) Theory PDM8QAM PDM-8QAM (cross) PDM-8SP16QAM ~ 4.0 dB 10 12 14 16 18 20 22 OSNR [dB]/0.1nm 24 26 o PDM-8SP16QAM and PDM-8QAM have similarly tolerance to optical noise 27 © Nokia 2016 Nokia Public Use -45 -55 -65 -75 1544.9 1545.3 wavelength [nm] 1545.7 PDM- 8SP16QAM (8 Set Partitioned 16QAM ) Theory PDM16QAM ~ 3.25 dB 8 Power [dBm] 14 13 12 11 10 9 8 7 6 5 4 Native RRC 0.1 -35 PDM- Cross 8QAM SP-QPSK WHAT’S THAT? Polar. X Polarization-based Polar. X Time-based 4D-SP-QPSK 4D-SP-QPSK 0 1 0 0 1 1 1 1 1 1 1 0 0 0 t 1 1 0 0 1 1 1 0 0 1 Q² factor [dB] Q² factor [dB] 10 8 0.5 dB 6 8 43GBd 4D-SP-QPSK w/o ROADM 10 8 14 16 18 43GBd 4D-SP-QPSK w/ ROADM 43GBd 4D-SP-QPSK w/o ROADM 32.5GBd PDM-QPSK w/ ROADM 32.5GBd PDM-QPSK w/o ROADM 6 4 Theory - 43GBd PDM-QPSK 6 20 OSNR [dB]/0.1nm © Nokia 2016 12 32.5GBd PDM-QPSK w/o ROADM Theory - 32.5 GBd PDM-QPSK 4 SP-QPSK 50GHz spacing, SSMF testbed (no DM) 14 10 Theory - 43 GBd 4D-SP-QPSK 12 No ROADM, SSMF testbed (no DM) 12 6 43 GBd PDM-QPSK 10 Does not require common phase recovery between the two polarizations 43 GBd 4D-SP-QPSK 32.5 GBd PDM-QPSK 8 Requires common phase recovery between the two polarizations Q² factor [dB] 14 12 Time Based t 1 1 0 0 Polar. Y Polar. Y 28 0 0 1 1 Polarization Based 8 10 12 14 # loops [x400 km] 16 18 20 4 6 8 10 12 14 # loops [x400 km] 16 18 • Back-to-back gain only about 0.5dB • About 2dB gain with transmission • Ideally used with super channels but still offers QPSK like performance through 50GHz filters Nokia Public Use 20 64QAM REALLY! 29 © Nokia 2016 Nokia Public Use TITLE 20 PT TREBUCHET SUBTITLE 16 PT TREBUCHET RailPictures.net ©Phil Cotterill used with permission Packing them in 30 © Nokia 2016 Nokia Public Use FLEXIBLE GRID SPECTRAL SHAPING AND SUPER CHANNELS 300GHz 50GHz SPECTRAL SHAPING -30 NRZ -35 100G RRC -40 -45 -50 6x100G QPSK bundled together from end to end for maximum transmission efficiency -55 -60 37.5GHz 50GHz -65 -70 1546.2 1546.3 1546.4 1546.5 1546.6 1546.7 1546.8 1546.9 1547 DSP-based spectral shaping at the Tx 100G 100G 225GHz 600G SUPERCHANNEL SPECTRAL SHAPING 31 © Nokia 2016 • Pulse-shaping functionalities on the 100G DSP allow transmitting narrower spectra • Enables tighter channels spacing with negligible transmission penalty • Combined with Flexgrid and Coherent filtering allows transporting “Superchannels” Nokia Public Use FLEXIBLE GRID COMES OF AGE 43GBAUD BASED SUPER CHANNELS 6 x 200Gb/s 16QAM in 300GHz New Formats Now Practical Through 43GBaud 100Gb/s SPQPSK 200Gb/s “8QAM” 50GHz 2014 200G ≈600km Reach 250Gb/s 16QAM 50GHz 2015 400Gb/s 64QAM ≈1500km Reach 200G 200G 6 x200Gb/s “8QAM” in 312.5GHz 32 © Nokia 2016 Nokia Public Use 3rd coherent generation Coherent Chips What is new? 64QAM (Flexible FEC) Flexible Modulation 16QAM 8QAM QPSK WSS Filter shape 100Gb/s – 5000km (>8Tb/s) 50Gb/s – 10,000km (>8Tb/s) BPSK 50GHz Programmable Modulation optimizes spectral density to the network 33 © Nokia 2016 Nokia Public Use THE OTHER PIECE WAVELENGTH ROUTING 34 © Nokia 2016 Nokia Public Use WAVELENGTH ROUTING BENEFITS ANALOGY FREEDOM TO EFFICIENTLY GET TRAFFIC WHERE YOU NEED IT 35 Must take assigned on-ramp Choose the best on-ramp Congestion, hard to divert Efficient utilization, easy to divert Slow new route utilization Fast new route utilization Running out of highway lanes Future proof flexible lanes © Nokia 2016 Nokia Public Use FLEXIBLE GRID COHERENT FILTERING 10G 100G DEMUX COHERENT RX The wavelength is selected by tuning the local laser in the RX Direct Detection RX COHERENT FILTERING 36 © Nokia 2016 • Coherent detection allows to perform filtering in the electrical domain • No need per-channel optical demux • Enables tighter channels spacing and “Superchannels” Nokia Public Use FLEXIBLE GRID ENABLING NARROWER AND FLEXIBLE CHANNEL SPACINGS 50 GHz 50GHz 37.5 GHz 75 GHz WSS 37.5 GHz FLEXIBLE GRID WSS 100 GHz 50 GHz FLEXGRID WSS 37 © Nokia 2016 • • • • LCoS-based WSS enables flexible and granular allocation of bandwidth 12.5 GHz granularity Enables advanced modulation formats for joint reach & spectral efficiency optimization Enables “Superchannels” Nokia Public Use BARRIERS TO WAVELENGTH NETWORKING Conventional ROADM architecture: CDC-F architecture: • Constrained • Highly agile • No truck rolls to route connectivity • Efficient add/drop block • Truck rolls to route connectivity • Inefficient add/drop block [1] • • • • Ports are color specific Ports are tied to a specific line A/D blocks support a specific color only once A/D blocks are separate for every direction [1] • • • • Ports are color independent (tunable) Ports are routable to all lines A/D blocks support a specific color when needed A/D blocks are pooled across lines and efficiently used [1] Based on “Flexible Architectures for Optical Transport Nodes and Networks”; S. Gringeri et al; IEEE Communications; July 2010 38 © Nokia 2016 Nokia Public Use BENEFITS OF WAVELENGTH ROUTING LOWER NETWORK COST OF OWNERSHIP WITH MORE SERVICE AGILITY 35 % Reduced CAPEX 30 % Reduced CAPEX $ New services 39 © Nokia 2016 SCALE AT THE MOST EFFICIENT LAYER: • capacity independent, in-service scale in all dimensions • greener – over 30% less power to switch light OPEX costs ROUTE WAVELENGTHS TO RECOVER NETWORK CAPACITY: • Eases OEO scale OPEX • no on-site visits required to route wavelengths costs GENERATE NEW REVENUE OPPORTUNITIES: • network agility to support SDN service goals • automated control to support new services/OAM applications Nokia Public Use OPEX costs WAVELENGTH ROUTING TO RECOVER CAPACITY EXTENDS NETWORK LIFESPAN Wavelength Demands A A A A B B B C C C D E E F BEFORE DEFRAGMENTATION B E F C D C G G G F E F G G 6 colors Sites A-B Sites A-C Sites A-D Sites B-E Sites C-F Sites D-E Sites D-F Sites E-G Sites F-G Site B Site A 30% recovery of network capacity Site C 4 colors Site E Site D AFTER DEFRAGMENTATION Site F 40 © Nokia 2016 Site G Nokia Public Use ADD AN OTN SWITCH True Value of Flexible Networks; G. Wellbrock, TJ Xia; M3A.1 OFC2015 41 © Nokia 2016 Nokia Public Use WHY BE FLEXIBLE? 42 © Nokia 2016 Nokia Public Use NEW YORK – SAN JOSE RFP DESIGN TO SUPPORT 88X100GB/S The ALU RFP response was for a line design to support 88x100Gb/s channels and included two regenerators 39x100G 58x100G 53x100G 70x100G 66x100G PDM-QPSK Regenerator Locations RFP Demands per segment shown in BLUE Congestion around east coast routes 43 © Nokia 2016 Nokia Public Use 84x100G ALTERNATIVE NEW YORK – SAN JOSE DESIGN USING MIXED FORMATS An alternative design using mixed modulation formats allows for relief of congestion on shorter east coast demands by using 200Gb/s 8QAM and greater reach on more lightly loaded segments by switching to 100Gb/s SPQPSK PDM-SPQPSK Regenerator Location 44 © Nokia 2016 Nokia Public Use PDM-8QAM MAINTAINING PERFORMANCE Bert van Dijk CC BY-SA 2.0 45 © Nokia 2016 Nokia Public Use OPTICAL TIME DOMAIN REFLECTOMETRY (OTDR) An embedded OTDR card to assist with; 1. Raman turn-up Provide point loss and reflection accuracy to within 1m for events within 2km, and 2m accuracy out to 20km during Raman turn-up Give visibility of the first external connector (with shortest pulse width setting) Provide an interactive “wizard” to simplify Raman turn-up 2. Fiber cut detection and location It will monitor both ends of the fiber Provide location accuracy to within 10m for cuts no further than 60km from either of the fiber ends, and for cuts that are further away (in loss or distance), the distance resolution may degrade to 15m Fibre plant is aging and much has issues which require monitoring 3. In-service loss distribution trending Store baseline at commissioning and flag significant changes 46 © Nokia 2016 Nokia Public Use OTDR Results – 75km Dark fiber OTDR Results – FIBER cut @ 50km Event 2: Connector @ 75km Event 1: Connector @ 50km 47 © Nokia 2016 Event 1 Signal Termination @ 50km Nokia Public Use OPTICAL CHANNEL TRACE Desired Configuration Due to device failure, provisioning failure or incorrect fibering at the degree 4 node, Service 1 and Service 2 are misdirected Service 1 Service 2 A Deployed Configuration: Intermediate Misconnection B A B C C D D The net result is misdirected traffic where one end is Service 1 and the other end is Service 2 48 © Nokia 2016 Nokia Public Use Because the future isn’t what it used to be……….. Alien Wavelengths An Alien Wavelength Interface / Demarcation is required Alien wavelength power adjustment and power balancing needs to be achieved Agnostic rate and format support to ensure compatibility with any of tomorrows formats OSNR Monitoring of alien wavelengths Automated commissioning and provisioning Threshold alarms ALU Line System ITU Optic Vendor x 49 © Nokia 2016 Nokia Public Use ITU Optic Vendor x 50 © Nokia 2016 Nokia Public Use