next generation multimode fiber technologies fia summer ... · next generation multimode fiber...

Next generation multimode fiber technologies

FIA Summer Seminar 2018

Carl [email protected]

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


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


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)


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


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


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


• 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


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)


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


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)


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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