Bend Bandwidth or Both

7/28/2019 Bend Bandwidth or Both

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Bend, Bandwidth or Both:

enterprise networksRavi Yekula



• Multimode fiber remains the most cost-effective

choice for enterprise networks – Multimode primer (classification and bandwidth)

– Benefits of multimode fiber (versus single-mode fiber and copper)

– Bend-insensitive multimode fiber

– Hi h Bandwidth OM4 fibers

– Next generation speeds (16 Gb/s, 40 Gb/s and 100Gb/s)



Multimode fiber types classifiedbased on bandwidth values

“OM” Core Diameter EMB OFL 850/1300 10G Linkes gna on µm z. m z. m eng

OM1 62.5 - 200/500 33 m

-

OM3 50 2000 1500/500 300 m

OM4 50 4700 3500/500 550 m

• Optical Multimode (OM) designations are per ISO/IEC11801

• EMB = Effective Modal Bandwidth (Laser BW)

• OFL = Overfilled Bandwidth (Legacy/LED BW)



Multimode fiber dominates in risers

In-Building Backbone• 80% fiber and increasing• 35% 1 Gb/s - 65% 100

Horizontal• Predominately Copper • 10/100/1000 Mb/s

a a cen ers

Mb/s

• Multimode fiber dominates, OM3 preferred(some OM4)

• Zone fiber growing

• 95% fiber and increasing• 10 Gb/s initial deployments• 70% 1Gb/s - 25% 100Mb/s• Fiber referred sin le-

Data Centers• 60% fiber and increasing•

Source: Corning Analysis

mode fiber continues togain

, , ,• Multimode fiber dominates,

OM3/OM4 strongly preferred



Historically, there have been manybenefits of fiber vs. copper

• Performance OM4

–

longer link lengths – Low latency

OM3

OM2 F i b e r

–

– Immune to EMI,

RFI and cross-talk –

0 100 200 300 400 500 600

Distance (m)

OM1 10 Gb/s Link Lengths at 850 nm

• Pathways andspace

–Cat6a

Cat7

p e r

,cables

Less cable fuelload

Cat5 10GBASE-T Link Lengths

Cat6

C o p

– Easier installationDistance (m)



With 10G the list of benefits of fiber vs. copper is growing

• Electronics portdensity, power and

10 Gb/s Operating CostFiber vs. Copper

Fiber Copper

coo ng e c enc es

= GREEN

Power Consumption

Coolin Re uirements

~0.5 W ~3-5 W

• Cost positionchanging with 10G Transceiver Size

– TIA Fiber Optic LANCost Model (fols.org)

–

Data Center Area$ $$$$

copper testing



Multimode fiber can save you money• Fixed costs ~ the

Fiber Optic Cable

same regardless of fiber choiceJumpers,

Connectors

• Transceiver costs ~¼ of total systemcosts

Patch Panel, Rack

< 1%

– Key area for savingswith multimode fiber Switch Electronics

74%

Fixed Cost

T ical 300 meter backbone

– difference in single-mode versusmultimode cable cost

Source: www.foundry.com, www.peppm.org, Corning analysis



Multimode fiber solution saves ~50%over single-mode fiber solution

• Assumptions – 300 m, 24 fiber count cable

– 24 fiber PassiveInterconnect (x2)

– 2

2.5

Relative System Costs: 1 Gigabit over 300m

Fiber Cable Hardware Tx/Rx

• Key findings: – Cable very small portion of

link costs

1.5

n m n m m - m o

d e

ma Δ or 10G capability

– MMF 850 nm (SX)solutions always lower cost

• OM3 fiber 0.5

1

1 3 0

1 3 0

8 5 0 n m

8 5 0 n

8 5 0 n

S i n g l

– Supports 10 Gb/s over 300m

– Lowest cost upgrade pathto 10G

0OM2 OM3 OM-2 (LX) OS-2 (LX)OM4

LX = Long Wavelength = 1300 nm

850 nm continues to provide cost benefit at 10G and beyond



850 nm continues to provide costbenefit at 10G and beyond

• 850 nm VCSELs ~90% of

• 850 nm 10G VCSELs justentering high-volume

s ransce vers

3.0

3.5

850nm

– 850 nm continues to be low-costsolution for 10 Gb/s

– Low cost solutions for 100 Gb/s 1.5

2.0

2.5

l a t i v

e C o s t

have been identified

– SFP+ 850nm transceiverscontinue to drive price down

0.0

0.5

1.0 R

capture some market share inenterprise networks –

Source: Corning estimates

2003 2005 2007 2009 2011Time



North American market now majority50 µm

Multimode Fiber Market Demand

65%

70%

75%

55%

60%

40%

45%

30%

35%

Q1 2005 Q1 2006 Q1 2007 Q1 2008 Q1 2009 Q1 2010

50 µm 62.5 µm

Source: Burroughs Report

More 50 µm sales than 62.5 µm sales since 2008



Laser-Optimized 50 µm continues togrow

50 micron Market Demand

65%

70%

75%

50%

55%

60%

35%

40%

45%

25%

30%

Q1 2005 Q1 2006 Q1 2007 Q1 2008 Q1 2009 Q1 2010

OM3/OM4

Source: Burroughs ReportOM3/OM4 has been majority of 50 µm since 2007



Lasers require new bandwidthmeasurement systems

Light Sources

• Designed to predict performance of low-speed LEDs, not lasers

•core, like LEDs

• Perturbations in index profile undetected (Typically 10 and 100 Mb/s)

ec ve o a an w

• DMD (Differential Mode Delay) basedmeasurement

• -

• Power distributed in a narrow region

• Simulates an actual laser launch

•

(1, 2, 4, 8, 10 Gb/s and higher)

high-speed laser-based systems



Characterization Methods

Fiber Core1 of 2 DMD-based standards compliant measurements

DMD (differential mode delay) Mask

BW defined by most delayed pulse

6 Masks Applied for OM3 (3 masks for OM4)

DMD output is “Normalized”

Fiber Core

≈5μm

TSlow TFast

Must only pass 1 mask to be OM3 (or OM4) compliant

25%

Laser

Laser

1-2 μm

Laser

Laser

TdelayPass = OM3 (2000 MHz.km EMB) or OM4 (4700 MHz.km EMB)Fail = OM2 (< 2000 MHz.km EMB)



Characterization MethodsFiber Core 1 of 2 DMD-based standards compliant measurements

Laser scanned across core

minEMBc (min Effective Modal BW – calc)

Ten weighting functions that simulate full range of laser output

characteristics are used along with DMD test results to calculate EMBcBW defined by most delayed pulse

e. . VCSEL #5er ore

≈5μmTSlow

TFast

Laser Laser Laser

Bandwidth value= 3128 MHz.km

e.g. VCSEL #3

Laser

Laser

Laser

Laser

Laser

Laser

= 2563 MHz.km

e.g. VCSEL #1Bandwidth value

T delay

“Hot inside” laser

Laser Laser Laser = 2137 MHz.km= 2137 MHz.km

minEMBc Value

Note: BW values provided for illustrations purposes only, drawing not scale

Different laser characteristics simulated

“Hot outside” laser

“Mid-range” laser



Multimode fiber preferred for enterprise networks

Single-mode Multimode

Distance supported X

Fiber price X

Connector price X

Transceiver price X

Ease of handling (core size) X

Multimode = Lowest price system for shorter links (10G to 600m) with manyterminations

- =

TIA and IEC recommends the use of laser-optimized 50 µm multimode fiber for backbone cabling because of its capability of supporting higher network speedsover onger s ances w e e ng more cos -e ec ve o mp emen an s ng e-mode fiber.



• Next generation multimode fibers and

standards – ,

and 100 Gb/s)

– -



OM4 Standard Approved by Internationaltan ar s rgan zat ons

• OM4 is 50 μm fiber with higher effective modal bandwidth than OM3

– x ra an w can e use or g er ra es, onger n eng s or

increased margin for more connectivity• Existing “OM” designations (per ISO/IEC 11801) are shown in the table

• IEC proposal for OM4 will be harmonized with TIA

“Type

oreDiameter

(µm)

(MHz.km)

5(MHz.km)

nLength

Link

Length

. - -

OM2 50 - 500/500 82 m -

OM3 50 2000 1500/500 300 m 100 m

OM4 50 4700 3500/500 550 m 150 m



Parallel optics are preferred for multimode fiber objectives

40 Gb/s

• 4 fibers x 10 Gb/s for transmit

• 4 fibers x 10 Gb/s for receive

100 Gb/s

• 10 fibers x 10 Gb/s for transmit

• 10 fibers x 10 Gb/s for receive



• The standard supports 40 Gb/s over:

– -

– At least 100m on OM3 MMF – At least 150m on OM4 MMF

–

– At least 1m over a backplane

• The standard supports 100 Gb/s over: – eas m on s ng e-mo e er

– At least 10km on single-mode fiber

– At least 100m on OM3 MMF

– At least 150m on OM4 MMF – At least 7m over a copper cable assembly

me er s ance a ows or . o connec or oss

OM4 150 meter distance allows for 1.0 dB of connector loss



Value proposition for OM4 dependson application

System Operating Link Length vs. Laser Bandwidth600

Applications

10G Ethernet

40/100G Ethernet400

500

n g t h ( m )

f i t

4G Fibre Channel100

200 L i n k l e

O

M 4 B e n

• Significant value for OM4 at 10G Ethernet

0

2000 2500 3000 3500 4000 4500 5000

Laser Bandwidth EMB (MHz.km)OM3 OM4

• Little value for OM4 at 4G regardless of EMB value – Dispersion limited because of broad spectral width

• 16G has tighter spectral width than 4G so value increases

• Although 40G/100G is based on 10G arrays, looser specifications for 40G/100Gtransceiver arrays significantly reduce the value



OM4 at 40G/100G extends costeffective MMF solution

•

on OM3 covers ~ 70% of data center links

– u e n c y

80%

100%

e q u e n c y

same level as OM4 allowsOM3 to support 120 m

• Extendin OM4 distance to l a t i v e F r e

40%

60%

u l

a t i v e F r

150 m with existingtransceivers covers ~ 90%of data center links

R

0%

20% C u

• OM3 and OM4 fibers cansupport even longer

Cable Length (m)

Length Distribution Cumulative Frequency,

spec change is required





Moves, adds and changes (MACs) can

look more like a rats nest

However…

Over time, MACs lead to mis-Initial installations that follow

managed cabling resulting in:• Congestion in sub-floor space

• Bend-induced attenuation

• Restricted air flow

bend radius guides andstructured cabling paths don’thave to worry about signal lossdue to inappropriate bends

• Negative impact on cooling efficiency



Data center “wish list” points toneed for effective cable management

• - terminated solutions

• Improve slack management

• Relieve congestion in pathways

• Improve airflow

• Eliminate polarity concerns

•



Cabling is Critical to NetworkPerformance

• Cablin is a relativel smallfraction of the initial network

spend• Cabling has the longest

expec e e me o e ma or network elements

• The potential for network

ElementPercentage of Overall Cost

ExpectedLifespan

high

• Cabling often an “afterthought”but it shouldn’t be

COMPUTERS 30% 3 years

SERVERS 20% 3 years

– Key to ensure that the cablingwon’t become the mostexpensive part of the network

CABLING10% 15 years

Source: Datalan-Network-Infrastructures



Fundamentals of macrobendingin multimode fiber

• Multimode fiber has many modes of light traveling through the core

• As each of these modes moves closer to the edge of the core it ismore likely to escape, especially if the fiber is bent

, ,amount of light that leaks out of the core increases

Dissipation of Coreenergy

Cladding



Bend-insensitive multimode fiber prevents light from escaping

• A specially engineered optical trench can be used to trap the energyin the many modes which propagate within the fiber core

• Keeping the light in the core, even in the most challenging bending-,



Standard OM3/OM4 fiber versusbend-insensitive OM3/OM4 fiber

Up to 10x better bend performance thanstandard 50 m fiber

10

)

High bandwidth OM3 and OM4capability

Im roved o tical erformance

1

b e n d l o

s s

, 2 t u r n s ( d

Fully standards compliant; Compatiblewith installed base

May be spliced/ connectorized with

0.1

M a c r

, 8 5 0 n

commercially available equipment.

5 7 9 11 13 15 17 19 21 23 25

Bend Radius (mm)

Multimode Std

IEC 60793-2-10

Multimode Std

ITU – G.651.1New Level of Bend

Performance

Bend Radius 37.5 mm 15 mm 7.5 mm

Number of Turns 100 2 2

.

New level of bend performance @

850 nm 0.05 dB 0.1 dB 0.2 dB



Typical Storage Area Network (SAN)link includes > 30 bends



Bend-insensitive OM3 fiber increases the spare margin

4

3

( d B )

Max IL and Margin for 300 m 10G link

Protected “Headroom” or SpareOperating Margin2

a l I n

s e r t i o n L o s

0

1 T o t

Inc rease Spare

System Margin

Protect Link Power

Bud et Conventional

OM3 fiber with bending

Loss

due tobending

Chromatic

Dispersion

Improved

Attenuation

Bend insensitive

OM3 fiber with bend

Benefits of Bend-Insensitive OM3



System DesignersCause of Downtime

• Cables and connectorsaccounted for 6% of downtime

43% of network downtime

Cost of Downtime

• Cost of downtime varies based

on organizational size• Network degradations are

more difficult to trace



Bend Insensitive multimode fiber is green

Drawing To ScaleSubstitute bend-insensitive multimode

Size of “box” with

bend insensitive50 µm fiber

fiber for conventional

50 µm fiber A B

Size of “box” with Loss of A = Loss of B Benefits µm fiber • Better cooling/airflow

• Reduced energy usage

If total energy costs are ~ 1M per year:

2% reduction $20,000/yr savings• Lower OPEX

• Smaller data center footprint

•



Make connector side-pulls anon-event

Standard 50 µm fiber Bend-insensitive 50



Keep your network clear with

bend-insensitive multimode fiber Standard 50 µm fiber

Bend-insensitive 50m fiber



Bend insensitive multimode fiber is fully standards

compliant and backwards compatible with installed base

• A well designed bend insensitive multimode fiber is fu l ly

• You can use bend insensitive multimode fiber with an

other standards-compliant 50 micron multimode fiber

a bend insensitive multimode fiber

• You do need the benefits of bend-insensitive multimodefiber in the enterprise network



• Multimode fiber remains the most cost-effective choiceor en erpr se ne wor s

• Bend-insensitive multimode fibers can help solve key

• OM4 fibers are now standardized and provide a path for

• Next generation standards will use OM3 and OM4 fibersto rovide low cost future- roof solutions for enter rise

networks

Documents

Bend Bandwidth or Both