optics for 100g and beyond

Guylain BarlowJDSU Network & Service Enablement

100G Client Interface Evolution

© 2014 JDS Uniphase Corporation | JDSU CONFIDENTIAL AND PROPRIETARY INFORMATION 2

Market Evolution• 100G Transceiver volumes

High-Speed Client Interfaces• Emerging Interface Types • Optics form Factor Evolution• Data Center Influence on Form Factors

Validating high-speed optics Evolution to 400G

Agenda


100G Interface Evolution

Infonetics 10G/40G/100G Optical Transceivers Oct. 2014

100G is now dominant in long-haulLR4 most popular as a client telecom interfaceData Center though is a key growth area

High Speed Interface TypesInterfaces & Form Factors


Current 100GE Interface Types

Interface Reach Medium Parallelism Standard

100GBASE-ER4 40 km SMF 4 λ / dir 802.3ba

100GBASE-LR4 10 km SMF 4 λ / dir 802.3ba

10x10 MSA (LR10) 2 or 10 km SMF 10 λ / dir 10x10 MSA

100GBASE-SR10 100 m125 m

OM3 MMFOM4 MMF

10 fibers / dir 802.3ba

100GBASE-SR4 70 m100 m

OM3 MMFOM4 MMF

10 fibers / dir 802.3bm

100GBASE-CR10 7 m Twin-axial electrical

10 cables / dir 802.3ba

100GBASE-CR4 4 m Twin-axial electrical

10 cables / dir 802.3bm

IEEE 802.3ba

• Main applications:• LR4: Most common interface in telecom by far• Key missing need is for reaches between 100m and 10km data center


100G Pluggables – Industry Roadmap

Client optics Current LR4 generation is the CFP2 with CFP4 soon coming CFP2 client optics are a 100G network enabler: lower power, lower cost and

higher density

25G I/O (or 10G) 10G I/O

10 physical electrical lanes

LR4 to 4 λCFP2

4 physical electrical lanes

LR4 to 4 λCFP

CFP CFP4 (2015/2016)

CFP2Now

Already in alpha/betaversion

LR4

LR4 & SR10

SR10CXP

QSFP28 (2016)

• CFP2/CFP4 for telecom for increased power & distance

• QSFP28 for data center for small size & low cost

CPAK


Compare to 10GE

A lot of form factors for 100GE to optimize There were even more for 10GE!

2000 2010

300-pin MSA

XFP

SFP+

Xenpak

X2

XPAK

25GE (802.3by)SFP28


Data Center Growth: 100G

Data Center core moving to 100G• Fueling the development of 25GE interfaces to Top of Rack Switches• Strong need for low cost client interfaces

Infonetics 10G/40G/100G Optical Transceivers Oct. 2014


100GE Client Connectivity Needs

Data Center• Backbone (inter-building) connects MDF (Main Distribution

Frame) to MDF. SMF between buildings• In-building MDF connects to Distribution Switches

100m is often too short a distance 10km is too costly Ribbon cables becoming common

Telecom• Current 10 km interface reaches most customers – not all• Key metro distance of 20 km+ becoming a requirement

Need 20km to 40km interface

Costly optics have kept 100G out of the datacenter – this is about to change


Upcoming 100GE Client Interfaces: 1 to 3 years away

Considerations for new interfaces based on 25G I/O for data centers:• 100GBASE-SR4 (802.3bm)

Four lanes on MMF 100 m. Key innovation is use of FEC RS(528,514) at PCS layer

• 100GE PSM4 (PSM4 MSA) SMF in the 1310 nm range for target distance of 500 m (also uses FEC)

• 100GE CWDM4 (CWDM4 MSA) & CLR4 & OpenOptics Discussions around 2 km range interface for SMF

In addition the following are being mentioned:• 100GE ER4-lite

Similar to ER4 for 40km but with use of FEC at PCS layer

Clear migration to all x4 interfaces for 100GE

SR4 125mPSM4 500m

CWDM4 2kmCLR4 2km

OpenOptics MSA 2km+


Medium Dependent Interface

Physical Medium Dependent

Reed Solomon Forward Error Correction

Physical Medium Attachment

Physical Coding Sublayer

(100) Gigabit Media Independent Interface

Logical Link Control

Media Access Control

From IEEE 802.3bj

Reconciliation Sublayer

Layer 1

Layer 2

Layer 3

Layer 4

Physical

Data Link

Network

Transport

OSI Model

Medium

MAC

RS

100GBASE-SR4

PMD

PMA

MDI

RS-FEC

CGMII

LLC

IP

100GBASE-R PCS

SR4 100GE Sublayers

• MM fiber at 25Gb/s has a lot of dispersion causing ISI, a FEC is required to get a link to work

• The same FEC block is used for passive copper, backplanes, SR4 and PSM4/CWDM4/CLR4/ER4-lite


RS-FEC

RS(528,514) used for 100GEBASE-SR4 (and KR4 and CR4), PSM4, CWDM4, ER4-lite

Symbol size of 10 bits 7 correctable symbols per FEC block 14 detectable symbol errors

Use of 64b/66b PCS to 256b/257b transcoder for RS-FEC layer (maintain throughput)• Such that the 100GE information rate remains 103.125 Gbits/s (25G per

lane)

Error Correction extends transmission distance for 25Gb/s lanes

…

Redundant area (14 symbols) Message area (514 symbols)

FEC Block (528 symbols)

symbol symbol symbol symbol


PSM4

Industry Consortium Group• Avago, Brocade, Delta Electronics, Finisar, JDSU, Juniper, Luxtera,

MACOM, Microsoft, Oclaro, Panduit, US Conec

Low cost solution to extend reach within data center for 100Gbps interconnects

Reach of 500m on parallel (ribbon) single mode fiber infrastructure• Sufficient within many data centers• Max power per lane: 2dBm, total of 8 dBm

Use of digital FEC to keep costs down


CWDM4 & CLR4

CWDM4 targets a common specification for low cost 100G optical interfaces up to 2 km

Data center applications Uses Coarse WDM technology with 4 lanes of 25 Gb/s on SMF CLR4 has similar targets to above at same wavelengths CWDM4 and CLR4 to interwork with CLR4 FEC on

Universal concept• Module convertible between SMF and MMF (shorter distance)• Can be aligned to CWDM4 wavelengths

CWDM4 CLR4

Tx Max power per lane

2.5 dBm 2.5 dBm

Rx Min power per lane

-11.5 dBm -12.5dBm (with FEC)-10 dBm (no FEC)

FEC Yes Yes or No

1217nm 1291nm 1311nm 1331nm


ER4-Lite

Key goal is to enable Metro and business services deployments with longer reach client interface

Current ER4 IEEE 820.3ba standard exists for 40km• No FEC• Technically challenging

Concept of ER4-Lite• Similar to ER4 BUT with potential use of RS(528, 514) FEC to

reach 40km• Proposed APD based specification for 40km reach


Connectivity

SR10 MMF ribbon, 10Gb/s 24 fibers: 10 active/dir Flat MPO/MTP connector

SR4 MMF ribbon, 25Gb/s 12 fibers: 4 active/dir Flat MPO/MTP connector

PSM4 SMF ribbon, 25Gb/s 12 fibers: 4 active/dir Angled MPO/MTP connector

CWDM4 / CLR4 Duplex SMF, 25Gb/s / λ

LR4/ER4 Duplex SMF, 25Gb/s / λ


Data Center Form Factor Challenges

In 1st gen 100G switches and routers, the smaller CXP form factor was used with MMF ribbon cables (SR10)

CFP or CFP2 is used for SMF transceivers This forced compromises as CXP ports could not be used with

SMF The QSFP28 form factor is set to resolve this dilemma

• A 1 rack-unit (RU) switch can accommodate up to 36 QSFP ports on the front faceplate

CXP

CFP


Generic Industry Roadmap

CFP CFP2 CFP4 QSFP28

Now

t

LR4 SR10 LR4 SR10

LR4

LR4

This is approximate to give a general idea of interface vs. form factorThis does not represent the view of any specific optics vendor

ER4

ER4-lite

ER4-lite

SR4

SR4 PSM4CWDM4

CWDM4

TelecomData Centers

ER4


QSFP28 increases front-panel density by 250% over 40G QSFP+• Lane speeds are increases 2.5-fold from 10 Gbps to 25 Gbps • Both are the same form factor

The increase in density is also considerable compared to other 100G form factors • 280%+ versus CFP2• 146%+ versus CFP4

Front Panel Relative Density

4 x CFP

8 x CFP2

16 x CFP4

24 x QSFP28

Belly-to-belly


What about Coherent Pluggables?

Slowly becoming available

Benefit is to have single line card supporting line or client interfaces

CFP & CFP2 exist for LR4, ER4, SR10

Coherent pluggables to support DP-QPSK; currently available

CFP• Common digital interface• Large pluggable size

CFP2 • Smaller, lower cost optics• Challenging electrical bus with off-optics DSP

Complex analog interface DSP to interoperate with multiple CFP2 vendors

CFP2DSP

Decoupled CFP2

Integrated CFP

Unit

Common digital interface

DSP CFP

Unit

Pluggable Characterization


Testing Pluggable Optics: Anatomy of Requirements

R&D and qualificationrequire COMPLIANCE testing

Field Troubleshootingrequires PERFORMANCE checking

Compliance

Check pattern sensitivity and crosstalk across lanes

Dynamic skew

Clock Tolerances, nominal jitter

Verify receiver sensitivity

Functionally verify communications with optics module (MDIO)

Electrical bus signal control

Performance

Focus on Error Rate performance

Test within clock tolerances

Verify operation within specified optical power range

CFPCFP2

Get acceptable error rate performance Validate designs

Note: Skew testing does not add to field test reliability – not required

CFP4QSFP28


BERT Testing Optics

Performance Test times depend on 3 factors:- Data Rate- Confidence Level- BER Threshold

95% CL 100GE BER Sec Min hrs

1E-12 29.09 0.48 1E-13 4.85 1E-14 48.48 0.811E-15 8.08

Bit Error Rate Test Time for a 95% Confidence Level depends on the line rate and BER target:

99% CL 100GE BER Sec Min hrs

1E-12 44.6 0.7 1E-13 7.4 1E-14 74.3 1.241E-15 12.39

New element with RS-FEC interfaces Pre-FEC tests (error rate BEFORE applying FEC) Post-FEC results (error rate AFTER FEC correction)


Compliance Testing Examples

Crosstalk patterns

Dynamic Skew

Frequency Variations

Electrical bus pulses


Line Side Impairment Testing

CLIENT SIDE (IEEE) LINE SIDE (ITU/OIF)

100GE Client 100G Coherent

Optical Stress

Data + Optical Stress

Loop traffic on MAPMeasure OSNR Penalty - OSNR is the new measure of distance Control Loss via attenuator Manipulate OSNR via ASE source & EDFA

Scramble polarization – fiber emulation Simulate ROADM Network Perform optical filtering to affect signal

shapeSimulate Fiber Scramble polarization

Run 100GE BER tests- Error Rate Results

JDSU ONT orMTS/T-BERD

JDSU MAP

For all tests, error evaluation through BER results

Evolution to 400G


400GE Client Considerations

400GE Client under discussion at IEEE 802.3bs Discussions include 8 lanes @ 50G and 4 lanes @ 100G 2015 view toward 2017 standard – All unconfirmed

• 400GBASE-SR16 & PSM4 (or 8) for data centers

• 400GBASE-LR8 for telecom• Use of higher order modulation (HOM) both electrical & optically

PAM-4 => adopted March 2015 for electrical interface

• Ethernet-level FEC mandatory No more error free native links – can assume < 10^-6 pre-FEC BER!

Media Interface Electrical Lanes Optical Modulation

MMF 100m 400GBASE-SR16 25G-per fiber NRZ

SMF 500m 400GBASE-PSM4 100G-per fiber PAM-4

SMF 2km 400GBASE-FR4 50G-λ PAM-4

SMF 10km 400GBASE-LR8 50G-λ PAM-4


Per Fiber Type Summary

Courtesy Ethernet Alliance


400GE Pluggable Form Factors under Considerations

Possible 400GE pluggable optics:• CDFP, mostly for active cables (short distance)

• Telecom form factors undecided Possibly will use CFP2

• May land on a CD-QSFP (QSFP sized) form factor in the very long run


Early Test Products

400GE module on ONT Demonstrated at OFC 2015 Pre-standard 400GE based on 25G I/O – 4xCFP2 Design to accelerate 400G product development, validation

and inter-operation

optics for 100g and beyond

Technology