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Next generation multimode fiber technologies
FIA Summer Seminar 2018
Carl Robertsrobertsc@corning.com
Optical Fiber 2
Agenda
• Map of fiber platforms and Data Center (DC) optics
• Fiber Choice is Dependent on Transceiver and Application
– Parallel vs. duplex: Application space for SWDM and OM5
• Interconnect Trends in DC and Standards Evolution for 100GE and Beyond
– Interconnect Trends in DC
– Break out capability
– Embedded optics (board mounted optical assembly)
– Single-mode encroaching on established multimode design space
• Multimode/Single-mode Fiber Cabling Trade-off: How to Solve it?
• Future Technology - Space Division Multiplexing
– Multi-core fiber
– Few-mode fiber
Optical Fiber 3
A Map of Fiber Platforms and Data Center OpticsIEEE Standard, in Standardisation, Proprietary or Multi Source Agreement
LCDuplex
MPOParallel
10G
40G
100G
100+G
40GBASE-SR440GBASE-eSR4
100GBASE-SR2100GBASE-SR4100GBASE-SR10100GBASE-eSR4
200GBASE-SR4400GBASE-SR16
MPOParallel
LCDuplex
The IEEE has defined a pathway to 40G and beyond based on MPO parallel connectivity for multimode and LC duplex for single-mode
Multimode Fiber Single-mode Fiber
50G
100G PSM4
200GBASE-DR4400GBASE-DR4
40GBASE-PLRL4
10GBASE-LR10GBASE-ER
40GBASE-FR440GBASE-LR440GBASE-ER440G UNIV
100GBASE-DR100GBASE-LR4100GBASE-ER4100G CWDM4
200GBASE-FR4200GBASE-LR4400GBASE-FR8400GBASE-LR8
50GBASE-FR50GBASE-LR
25GBASE-LR25GBASE-ER
10GBASE-SR
40G BiDi40G SWDM
40G UNIV
100G BiDi100G SWDM
50GBASE-SR
25GBASE-SR25G
PathwayNot Defined
Optical Fiber 4
Fiber Choice is Dependent on Transceiver and Application
LCDuplex
MPOParallel
40G
100G
100+G
40GBASE-SR440GBASE-eSR4
100GBASE-SR2100GBASE-SR4100GBASE-SR10100GBASE-eSR4
40G BiDi40G SWDM
100G BiDi100G SWDM
200GBASE-SR4400GBASE-SR16
Single transceiverWDM transceiver
OM3/4 are compatiblewith WDM transceivers
OM5 offers extendedrange for WDMtransceivers
OM3/4 are optimized forsingle transceivers
OM3/4 are optimized at 850 nm to match the single utilized by parallel transceiversOM3/4 are also compatible and specified for use by WDM transceiversOM5 is specifically optimized for WDM operation at distances above 100 m at 100G
MMF
PathwayNot Defined
Corning Optical Communications 5© 2017 Corning Incorporated
SWDM and OM5Bandwidth and Chromatic Dispersion relationship
• At 840 nm, fiber is NOT limited by bandwidth, but by chromatic dispersion
– Chromatic Dispersion decreases at longer wavelengths
• At longer wavelengths, attenuation and dispersion characteristics improve, however modal bandwidth decreases.
• By maintaining a 100 m target length, which covers >90% of data centre links, a solution can be realised within a window of operation.
VCSEL
850 nm
880 nm
910 nm
940 nm
MU
X
DEM
UXVCSEL
VCSEL
VCSEL
1
2
3
4
1 2 3 4
1
2
3
4
Corning Optical Communications 6© 2017 Corning Incorporated
Fiber Summary for Multimode Fiber Infrastructure
• Parallel connectivity is the most versatile architecture
– Enables the use of low cost single wavelength 850nm transceivers
– Provides the most flexible breakout options
– Is widely supported by standards
Best fiber choice for parallel systems: OM4 (WDM is not used in parallel systems)
• Duplex is a legacy architecture used in standards based systems up to 10G. Although non-standardized, new WDM transceiver technology enables migration to 40G and 100G by maintaining existing duplex fiber infrastructure.
Data Rate WDM Transceiver OM3 OM4 OM5
40GBiDi 100m 150m 200m
SWDM 240m 350m 440m
100GBiDi 70m 100m 150m
SWDM 75m 100m 150m
Corning Optical Communications 7© 2017 Corning Incorporated
Interconnect Trends in DC and Standard Evolution for 100GE and Beyond
Link Length
from 10G/40G
100 m over Multimode OM4
100 m over Multimode OM4
Migration path
500m over Single-mode
100G/400G: Cloud services and Hyperscale DC drive the increasing need forbandwidth: single λ100G PAM4 expected to enable the lowest cost for 100G and400G transceivers that can fit in SFP and QSFP on single-mode
Next move - in standardization
to 50G/200G to 100G/400G
50GBASE-SR(50Gb/s PAM4)
100GBASE-DR(Single λ 100Gb/s PAM4)
500 m over Single-mode
200GBASE-SR4(4f each 50Gb/s PAM4 per direction)
On existing MMF OM4 based-8f parallel cabling
200GBASE-DR4(4f each 50Gb/s PAM4per direction)
400GBASE-DR4(4f each 100Gb/s PAM4per direction)
Today standardized
to 25G/100G
25GBASE-SR(25Gb/s NRZ)
100GBASE-SR4(4f each 25Gb/s NRZ per direction)
On existing MMF OM4 based-8f parallel cabling
100G PSM4 MSA(4f each 25Gb/s NRZ per direction)
Corning Optical Communications 8© 2017 Corning Incorporated
Break Out Capability
• Breakout and shuffle capability of DC cabling is fundamental, especially for DC with Spine-and-Leaf 2-Level architecture.– Only possible with parallel optic cabling, e.g. a 40G in 4 ports @ 10G,
100G in 4 ports @ 25G
– Switch migration path with cost saving per port and less power consumption
• Duplex WDM cannot be broken out to separate the single lane connections
Corning Optical Communications 9© 2017 Corning Incorporated
Embedded Optics (on-board optics or board mounted optical assembly)
• Adoption in DC
– Reduction of signal trace length at higher data rates requires close proximity of optics with ASIC
– Enabling 5x-10x denser I/O than edge mounted pluggable optics
– Consortium for On-Board Optics (COBO)
• MM and SM
• ASIC I/O density greater than pluggable line card density (400G)
Source: Avago
Corning Optical Communications 10© 2017 Corning Incorporated
Single-mode Encroaching on Established Multimode Design Space
• Multimode has been the standard fiber of choice for lengths < 100 m
• The advancement of hyper-scale data centres has led to single-mode fibre being deployed within the multimode application space
• Multimode is expected to remain the fibre of choice for short lengths and patching
• This leads to a complexity of cable solutions within intermediate cable lengths
• A solution is required to simplify the overall fibre and cable choice across the entire data centre.
Source: Corning
Corning Optical Communications 11© 2017 Corning Incorporated
• Fiber Design
– Maintains single-mode propagation due to matched Mode Field Diameter for LP01
fundamental mode at 1310 nm
– Loss is on par with normal SM transmission
– Core is still large enough to couple light from 850 nm VCSEL
Universal Fiber (UF): MMF concept designed to support both multimode and single-mode transceivers
VCSELUse multimode
50umMM30um~SM LP01 MFD UF
Universal Fiber can accept multimode launch
Single-mode LaserUse fundamental mode
SM LP01 MFDSM
30um~SM LP01 MFD
UF
Universal Fiber can accept single-mode launch
Concept achieved >100m for common 40G and 100G transceivers
Corning Optical Communications 12© 2017 Corning Incorporated
Space Division Multiplexing Offers a Possible Path to Further Capacity Increases
Higher pulse rates (baud rate)
More bits per symbol
Polarization multiplexing
QPSK 16-QAM2 bits/symbol 4 bits/symbol
More optical carriers and denser wavelength division multiplexing
Space Division Multiplexing (multicore or few-moded fibers)
Corning Optical Communications 13© 2017 Corning Incorporated
Multicore Fibers and Few Mode Fiber Made in Corning
Mode Division Multiplexing• Use each spatial mode to transmit WDM signals
Large core supports multiple modes• Increase effective area beyond the limit (~150 µm2) for single mode fiber
Transmission demonstrations• 1 Pb/s over 14 core fiber • Short reach over 8 core fiber• Short reach over 2 core
Corning Optical Communications 14© 2017 Corning Incorporated
Practical use of MCF/FMF requires other technology developments
Overcome crosstalk between different cores (MCF) and different modes (FMF)
Manufacturing MUX/DEMUX and amplifiers for MCF and FMF on a production scale
Development of low cost manufacturing processes
Changes to installation processes i.e. splicing and connectorization
Mu
lti-
core
Fib
ers
(MC
F)Fe
w-m
od
e Fi
ber
s (F
MF)
Corning Optical Communications 15© 2017 Corning Incorporated
Conclusions
• DC capacity challenges drive continued innovation in optical fiber
• Recently published OM5 standard delivers one route to increased capacity and reach over multimode WDM transceivers
• Other fundamental fibre design innovations are being investigated for the longer term including:
– Embedded Optics
– Universal Fiber
– Multi Core Fiber
– Few Mode Fiber
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