the future of optical fibre in data centers rick pimpinella (panduit) l1 2018 1.pdfthe future of...

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© 2018 Panduit Corp. All Rights Reserved

The future of optical fibre in data centers

Dr. Rick Pimpinella, Panduit Fellow

Optical Fibre Research

Member IEEE

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© 2018 Panduit Corp. All Rights Reserved.

MMF will continue to provide 3 major benefits

1. Lower cost than single-mode data communicationsa) MM VCSEL transceivers are less expensive than SM DFB laser transceivers

b) Relaxed manufacturing tolerances

c) Lower transceiver power consumption

2. More robust connectivitya) Components more tolerant to dirt and dust

b) Connectors do not require high return loss

c) No multipath interference

d) More forgiving to long-term connector degradation

3. Meets Data Centre & Enterprise reach & bandwidth requirementsa) For foreseeable future (> 15 years)

Multimode fibre will be the main focus of this presentation

VCSEL DFB

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Technical Overview

• Differences between MMF types

‒ Fundamental properties of MMF

‒ Optical channel penalties

• Future applications for MMF in the DC

‒ Parallel optics vs. SWDM

• Single-mode fibre & application

• Looking forward more than 15 years out

‒ Future proofing your network

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MN 0.3dB

3.02dB

1.5dB (connectors)

+ 1.1dB (fibre)

2.6dB

0.8dB

MPN 0.07dB

RIN 0.17dB

Correction Noise 0.36dB0.90dB

Inter-Symbol Interference

Due to transmitter jitter

& fibre dispersion

Power

Budget

(dB)

IL

Margin

8

7

6

5

4

3

2

1

0

Polarization Noise 0dB

Reflection Noise 0dB

ISI

10 GbE Optical Power Budget for MMF

IL is independent of data rate

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Channel insertion lossFor VCSEL Transmission Over MMF

0

100

200

300

400

500

600

1GbE 10GbE 40GbE 100GbE 128GbE

Max

imu

m R

each

(m

)

Data Rate

Multimode Channel Reach & Channel IL

Fibre IL = 1.93 dB

Fibre IL = 1.05 dB

Fibre IL = 0.52 dB

Fibre IL = 0.35 dB

Fibre IL = 0.30 dB

Bit RateReach

(m)Fibre Type

1 GbE 550 OM2

10 GbE 300 OM3

40 GbE 150 OM4

100 GbE 100 OM4/OM5

128 GbE 85 OM4/OM5

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3.25 dB Inter-Symbol Interference

Due to fibre dispersion effects

1.5 dB (connectors)

+ 0.4 dB (fibre)

1.9 dB

Power

Budget

(dB)

IL

8

7

6

5

4

3

2

1

0

ISI

100G BASE-SR4 Optical Power Budget For MMF

1.85 dB Transmitter Jitter5.1 dB

ISI is the limiting power penalty in high-speed links

Modal Noise

Mode Partition Noise

Relative Intensity Noise

Correction Noise

1.2 dB

Reflection Noise

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Multimode Fibre ModesA pulse of light splits and travels along different optical paths called “modes”

3 of 380 possible modes (optical paths)

Caustic Surfaces

Skew Mode

Fiber Core

Meridian Plane Through Optic Axis

Fiber Core

a

Fiber Core

Fibre Core

Cladding

RR = 25 microns

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1.44

1.445

1.45

1.455

1.46

1.465

1.47

-35 -30 -25 -20 -15 -10 -5 0 5 10 15 20 25 30 35

1.44

1.445

1.45

1.455

1.46

1.465

1.47

-35 -30 -25 -20 -15 -10 -5 0 5 10 15 20 25 30 35

n

Manufacturing Variation in Refractive Index Profile

1.44

1.47

1.44

1.47

n

r

0R=25mm

n1

n2

Core

Cladding

D = 1.02 %

n

cv

2

1

2

2

2

1

2n

nn D

2/1

1 21

D

a

R

rnrn

where,

a ~ 2 for 850 nm250/50 probability

1

2

1.44

1.47

1.44

1.47

n

r

0R=25mm

n1

n2

Core

Cladding

D = 1.02 %

n

cv

2

1

2

2

2

1

2n

nn D

2/1

1 21

D

a

R

rnrn

where,

a ~ 2 for 850 nm2

a2 >a0

a1 <a0

R = 25 mm

n1

R

a0

where, c = speed of light in vacuum

= 299,792,458 meters per second

n2

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ISI Contribution No. 1 – Modal Dispersion

Input Data

Multimode fiber core

Pulse broadening

Output bits

Two sequential data bits “Symbols” Modal dispersion Inter-symbol Interference

2 data bits

2 a1 > a0

t

t+Dt

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IEEE Link Model Calculated Channel Reach For Cisco’s 40G BiDi

50

60

70

80

90

100

110

120

130

140

150

820 830 840 850 860 870 880 890 900 910 920 930 940 950

Rea

ch

(m

)

Wavelength (nm)

Panduit’s Signature Core™ OM4+ fibre

l1 l2

Reach Requirement

Standard OM4 multimode fibre

1

2

• Reaches using Measured EMB Wavelength Dependence

• a1 multimode fibres support longer wavelengths (SWDM)

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ISI contribution No. 3 – Chromatic dispersion Different wavelengths travel at different velocities

Laser MMF Core

Shorter wavelengths

travel slower

Pulse broadening

due to chromatic

dispersion

+i i

i

C

Bn

2

22 1

l

ll

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ISI contribution No. 4 – Modal-Chromatic dispersion Modes undergo a relative chromatic dispersion – Panduit discovery

MMF Core

l2

l1

Laser

• Combination of Modal & Chromatic disp’n

• Effect previously unknown

• Can be compensated by a1

850.452 nm 850.028 nm 849.584 nm 849.108 nml2 = l1 =

a0 fibre

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1.E-14

1.E-13

1.E-12

1.E-11

1.E-10

1.E-09

1.E-08

1.E-07

1.E-06

1.E-05

1.E-04

1.E-03

-13.0

-12.5

-12.0

-11.5

-11.0

-10.5

-10.0

-9.5

-9.0

-8.5

-8.0

-7.5

-7.0

Rx Power (dBm)

Impact of modal-chromatic dispersion- Same fibre manufacturer, cable, and bandwidth (4700 MHz·km)

Ch

an

ne

l b

it e

rro

r ra

te @

10

Gb

/s

PASSCompensations

MC dispersion

FAILExacerbates

MC dispersion

HigherPerformance

LowerPerformance

1

2

C26 Blue

C26 Brown

• 10 Gb/s Ethernet

• Same transceiver (850 nm)

• 300 m reach

• IEEE 802.3ae requirement, 1E-12 @ -9.9 dBm

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Multimode fibre types

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Laser Optimized Multimode Fibre TypesFibre Sorted and Classified Based on Quality of Modal Dispersion

Fibre TypeEMB at 850 nm

(MHz·km)

EMB at 953 nm

(MHz·km)

OM3 2000 NA

OM4 4700 NA

OM5 4700 2470

Signature Core OM4+ 5500 2000

• MMF is sorted as OM3 & OM4 based on Effective Modal Bandwidth (EMB)

• EMB is calculated from a Differential Mode Delay (DMD) measurement, i.e., modal dispersion

• OM3 and OM4 are designed for 850nm transmission and minimum channel reaches of 100 m and 150 m respectively

• OM5 includes a specified EMB at a longer wavelength (953nm)• Only provides a benefit for SWDM-4 applications where the required reach exceeds the standards specified

maximum channel reach (non-standard)

• Signature Core OM4+ is a dispersion compensating (a1) OM4 fibre

50% a1 & 50% a2

50% a1 & 50% a2

~ a1

Only a1

Alpha profiles

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OM5 – Wide Band Multimode Fibre

• OM5 was developed under a TIA Joint Task Group ‒ Organized under the TR42.12 and TR42.11 Subcommittees

‒ TR42-12 Vice-Chaired by Panduit, Dr. Brett Lane

‒ Task Group Chaired by Panduit

‒ EMB shifted for longer wavelength operation‒ Higher bandwidth at 953 nm

‒ Similar bandwidth at 850 nm

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TIA Round Robin ReportUsed For Specifying OM5 Chromatic Dispersion

Source: TR42.12-2015-06-022

Round Robin

Participants

1. Corning

2. OFS

3. Panduit

4. Prysmian

5. J fibre

6. YOFC

Standard MMF

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Future of Multimode FibreLowest cost for short reach applications

Switch-to-server interconnections

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Optical

Transmitter

Optical

Transmitter

Optical

Transmitter

Optical

Transmitter

PMD

Service

Interface

MDI

Optical

Receiver

Optical

Receiver

Optical

Receiver

Optical

Receiver

PMD

Service

Interface

L0

L1

L2

L3

L0

L1

L2

L3

l0

l0

l0

l0

Patch

Cord

Multimode Optical

fibre Cable

MDI

4 fibres x 50 Gb/s(parallel optics)

Supports Breakout Functionality

Block Diagram For 200 GbE Parallel Optics Transmit/Receive Paths

For clarity, only one direction of transmission is shown

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32 25

48 Servers

Patch Panel

.

.

.

ASIC

256 x 50G

…

…

…

…

1 -

86

4

65 - 72 128

12

9 -

13

61

92

193 -200256

40

0G

1 2 6 24

40

0G

40

0G

40

0G

40

0G

40

0G

48 Servers

Patch Panel

.

.

.48 Servers

Patch Panel

.

.

.48 Servers

Patch Panel

.

.

.

…

…

…

. . .

6 x 8 = 48

50G servers

. . .

Multimode Fibre Application: Server BreakoutEx: 256 x 50G Switch Radix – 3:1 Over Subscription

• ASIC – Application Specific Integrated Circuit

• High density 32 x 400G switch ports

• 50G servers supported by- 400GBASE-SR8 to 50GBASE-SR breakout

8 x 400G (64 x 50G) Uplinks (3.2 Tb)

24x 400G (192 x 50G) Downlinks (9.6 Tb)

4 racks of 48 servers

6 switch ports / Rack

6x 16f MPO to 48 duplex LCs

4 rack of 48 servers

or

8 racks of 24 servers

40

0G

40

0G

40

0G

40

0G

40

0G

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SWDM = Short Wavelength Division MultiplexingMDI – Media Dependent InterfacePMD = Physical Media Dependent

Optical

Transmitter

Optical

Transmitter

Optical

Transmitter

Optical

Transmitter

PMD

Service

Interface

MDI

SW

D M

ux

SW

D d

eM

ux

Optical

Receiver

Optical

Receiver

Optical

Receiver

Optical

Receiver

PMD

Service

Interface

L0

L1

L2

L3

L0

L1

L2

L3

l0

l1

l2

l3

l0

l1

l2

l3

Patch

CordSingle-mode fibre

MDI

4 l’s x 50G

Block Diagram For SWDM4 Transmit/Receive Path

For clarity, only one direction of transmission is shown

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• SWDM requires a filter for each l, each filter adds an insertion loss ≥1.5 dB dB

• End-to-end (TX & RX) has a reduction in signal power ≥3dB

• Has a 3 dB reduction in SNR compared to parallel optics

• SWDM/OM5 Channels will have reduced reach compared to parallel optics

• Does not support port breakout

SWDM Transmission

Cross-talk

l0

l1

l2

l3

p+

n+

i

SiO2

p+

n+

i

SiO2

p+

n+

i

n-contact

p-contactsAntireflective

coating

SiO2

l0

l1 l2 l3l0 Detector

l2 Detector l2 Detector l3 Detector

p+

n+

i

Si O

2

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Double Link Channel Cost ComparisonIEEE Panduit contribution (pimpinella_NGMMF_03_0118.pdf)

200GBASE-SR4 200G SWDM4 115 mn d4.0 1.75

7.00296.00$ 518.00$

Parallel Cabling Duplex Cabling

Fiber Type = OM4 OM5

12 12

8 2

2 2

3 3

0.53 0.82

0.08 0.11

0.51 0.77

1.00 0.25

Cable fiber count =

XCVR TYPES: Cost crossover =

Cost multipliers =

Total Xcvr cost factor =

STRUCTURED CABLING:

No. of used fibers =

No. of channel links =

No. of patch cords =

Normalized Standard Costs

Material + Labor

Cable Termination =

Per meter adder =

Adapter panel or Cassette =

Patch Cord =

0.75

1.00

1.25

1.50

1.75

2.00

0 50 100 150 200 250 300

2 X

cvrs

Plu

s St

ruct

ure

d C

ab

ling

(R

ela

tive

Co

st)

Channel Reach (m)

Channel Cost Analysis

200G SWDM4

200GBASE-SR4

0.68 W 1.0 W

0.25 X1.0 X

0.65 Y 1.0 Y

0.81 Z 1.0 Z

n = cost multiplier compared to 10GBASE-SR

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Panduit contribution to IEEE – Eye safety calculatorParameter Units Notes

l = nm Wavelength each lane

Power = dBm Poewr each lane

NA = - Numberical Aperture + tolerance

N_fiber_vert - Number of fiber rows

N_fibers_horiz - Number of lit fibers in row

Distance_y mm Fiber row separtion distance

Distance_x mm Fiber pitch within row

Source size (one) mm MMF core diameter

1 = Telescope condition 1 2 3 1 2 3 1 2 3 1 2 3 Telescope, microscope, naked eye

2 = Microscope d 0 = 7.0 3.5 7.0 7.0 3.5 7.0 7.0 3.5 7.0 7.0 3.5 7.0 mm Stop aperture

3 = Naked eye L = 2000 14 100 2000 14.0 100 2000 14 100 2000 14 100 mm Source-aperture separation

worst_comb_y 1.00 1.00 1.00 1.0 1.0 1.0 1.00 1.00 1.00 1.00 1.00 1.00

worst_comb_x 1.00 1.00 1.00 1.0 1.0 1.0 1.00 1.00 1.00 1.00 1.00 1.00

total_fibers 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 Number of fibers in field of view

alpha (worst) 1.50 3.57 1.50 1.50 3.57 1.50 1.50 3.57 1.50 1.50 3.57 1.50 mrad Subtense source angle

T2 10.00 10.50 10.00 10.00 10.50 10.00 10.00 10.50 10.00 10.00 10.50 10.00 sec Emission durationd 63 = 410.83 2.88 20.54 374.05 2.62 18.70 383.83 2.69 19.19 405.91 2.84 20.30 mm Beam diam. 63%

C4 = 1.941 1.941 1.941 2.228 2.228 2.228 2.559 2.559 2.559 2.938 2.938 2.938 Correction factor 4

C6 = 1.00 2.38 1.00 1.00 2.38 1.00 1.00 2.38 1.00 1.00 2.38 1.00 Correction factor 6

C7 = 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 - Correction factor 7

h 0.000 0.773 0.110 0.000 0.833 0.131 0.000 0.817 0.125 0.000 0.781 0.112 - Fraction of power accessible

Class 1 AEL 0.757 1.797 0.757 0.869 2.063 0.869 0.998 2.369 0.998 1.146 2.720 1.146 mW

Class 1M AEL 0.757 500.000 0.757 0.869 500.000 0.869 0.998 500.000 0.998 1.146 500.000 1.146 mW

2607.67 2.33 6.90 2482.02 2.48 6.65 3000.69 2.90 8.01 3852.91 3.48 10.22 mW

500.00 500.00 6.90 500.00 500.00 6.65 500.00 500.00 8.01 500.00 500.00 10.22 mW

1.884 1.884 1.884 1.884 1.884 1.884 1.884 1.884 1.884 1.884 1.884 1.884 mW

0.0007 0.8098 0.2728 0.0008 0.7600 0.2833 0.0006 0.6494 0.2351 0.0005 0.5406 0.1844 -

0.0038 0.0038 0.2728 0.0038 0.0038 0.2833 0.0038 0.0038 0.2351 0.0038 0.0038 0.1844 -

Class 1

Class 1M

Bi-directional = 01

Co-directional = 1

1.0

Class 1, 1M Emission Limits for range Wavelength 1 Wavelength 2

700 nm to 1399 nm 844 874

2.75 2.75

Wavelength 3 Wavelength 4

Hazard per wavelength per conditions Class 1M =

Condition

Class 1 Hazard 2.760 EXCEEDED

Class 1M Hazard 0.976 PASS

AEL per Class/condition

Max permissible power for hazerd 1:

Total Power per wavelength per condition:

Hazard per wavelength per conditions Class 1 =

Max permisible power for hazerd 1M:

Maximum Level

per wavelength

0.810 0.760

0.273 0.283

0.649 0.541

0.235 0.184Worst case for each wavelength

0.05

904

2.75

0.161

934

2.75

0.1700.172 0.157

1.0

0.25

0.25

1.0 = Hazard

Based on

measured

VCSELs

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Progression of Multimode Fibre Ethernet PMDs

Data Rate

Gb/sNomenclature

Lane Rate

Gb/s

Number

of

fibre pairs

Number of

wavelengths

Year

Standardized

10

40

10GBASE-SR

40GBASE-SR410

1

41

2002

2015

25

100

25GBASE-SR

100GBASE-SR425

1

41

2016

2015

50

100

200

50GBASE-SR

100GBASE-SR2

200GBASE-SR450

1

2

4

8

12018

400400GBASE-SR8

~2021400GBASE-SR4.2 4 2 BiDi

100

200

400

800

100GBASE-SR

200GBASE-SR2

400GBASE-SR4

800GBASE-SR8

100

1

2

4

8

1 TBD100G PMD

Series

50G PMD

Series

10G PMD

Series

25G PMD

Series

NEW

FUTURE?

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Multimode fibre structured cabling channel Lengths

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

0.0%

2.0%

4.0%

6.0%

8.0%

10.0%

12.0%

14.0%

16.0%

18.0%

20.0%

Cum

ula

tive %

% o

f channel le

ngth

s (

m)

Channel Length (m)

90% of channels less than 100 m

96.5% of channels less than 150 m

Source: Ethernet Alliance 23 March 2016

96.5%

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Single-mode FibreRequired for Long or Extended reach Applications

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Single-mode fiber types specified by ITU-T

OS2

CCITT – International Telegraph and Telephone Consultative Committee ITU – International Telegraph Union (1864), Now known as International Telecommunications Union

1988

2006/2009

NewSPS

2012

1984CCITT

Blue Book

2000

RecentlyApproved

SPS-433For

G.652.D

2003

ITU-T

SpecIEC Description OFS Corning Prysmian

1 G.652.A “Standard” SMF w/ ZDW ~1310nm. AllWave SMF-28

“Standard” SMF w/ ZDW ~1310nm,

1625nm Atten, low PMD.

“Standard” SMF w/ ZDW ~1310nm,

LWP, low PMD.5 G.653.A Dispersion –Shifted SMF. Not branded.Offered upon request.6 G.653.B Dispersion –Shifted SMF, Low PMD. Not branded. Offered upon request.7 G.654.A - Cutoff-Shifted SMF. Obsolete8 G.654.B B1.2_b Cutoff-Shifted SMF, med MFD, low PMD. TeraWave 9 G.654.C B1.2_c Cutoff-Shifted SMF, low PMD. TeraWave 10 G.654.D - Cutoff-Shifted SMF, high MFD, low PMD. TeraWave Ocean SLA+ / ULA Vascade LongLine

Non-Zero Dispersion Shifted SMF, low TrueWave RS,

1625nm bend. TrueWave LA (Large Area)

Non-Zero Dispersion Shifted SMF, positive TeraLight,

dispersion, low 1625nm bend. TeraLight Ultra

14 G.656 B5 Non-Zero Dispersion Shifted SMF for Wideband. TrueWave REACHTeraLight,

TeraLight Ultra

16 G.657.A2 B6_aBending-Loss Insensitive SMF, r =7.5mm,

G.652.D compliant. AllWave FLEX+ClearCurve LBL BendBright-XS

17 G.657.B2 B6_b Bending-Loss Insensitive SMF, r =7.5mm AllWave FLEX Max ClearCurve LBL BendBright-XS

AllWave FLEX Max, EZ-Bend (r=2.5mm)

B1.12 G.652.B AllWave SSMF

3 G.652 C B1.3 AllWave“Standard” SMF w/ ZDW ~1310nm, LWP

4 G.652 D B1.3 AllWave, AllWave FLEXSMF-28e

SMF-28e+ESMF

B2

11 G.655.C B4_c Non-Zero Dispersion Shifted SMF Leaf

12 G.655.D B4_d Leaf

TrueWave RS, TrueWave REACH,

TrueWave LA (Large Area)

13 G.655.E B4_e TrueWave REACH

15 G.657.A1 B6_aBending-Loss Insensitive SMF, r =10mm, G.652.D

compliant.ClearCurve XB Bendbright

18 G.657.B3 B6_b Bending-Loss Insensitive SMF, r =5mm ClearCurve ZBL BrendBright Elite

AllWave+

OS1Obsolete

Transitioning

away from

G.652.D (OS2)

31

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Hyperscale data center Ethernet Market

50/100/200/400GE

Approaches 50% of All

Data Center Ports by 2021

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IEEE 802.3 MMF Ethernet Data Rate Timeline

2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 2023 2024 2025 2026 2027 2028

10/40GbE Ecosystem802.3ba

802.3bj

802.3bm

802.3by

25/100GbE Ecosystem

42.11 SWDM Ecosystem 50-200GTIA Wide-band MMF (OM5)

Single-lane 25G

Twin-ax

4x25G

n x 100G PAM-4 Ecosystem

n x 50G PAM-4 Ecosystem 50-400G802.3cd

n x 64G PAM-4 EcosystemFC PI-7

802.3 CFI

We are here

YEAR

• MMF will support future higher-speed Ethernet

• Maximum data rate determines maximum reach

• SMF required for reach > 150 m

• Parallel optics is best choice for future proofing

Summary:

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The future of optical fibre in the data centerDr. Rick Pimpinella, Panduit Fellow

THANK YOU

the future of optical fibre in data centers rick pimpinella (panduit) l1 2018 1.pdfthe future of...

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