1060nm VCSEL --based 10Gbps optical interconnects · 1060nm VCSEL --based 10Gbps optical...

1060nm VCSEL1060nm VCSEL--based 10Gbpsbased 10Gbps1060nm VCSEL1060nm VCSEL--based 10Gbpsbased 10Gbpsoptical interconnectsoptical interconnects

Hideyuki Nasu

Technical seminar at CERN, Sept. 23 2011H. Nasu/FITEL Phonics Laboratory, Furukawa Electric Co, Ltd.

FITEL Photonics LaboratoryFurukawa Electric Co., Ltd.

Outline

� Background� Why we need optical interconnects?� Trends in optical interconnects

� Advantage of 1-µm optical interconnect� InGaAs VCSEL and PD

�Low power consumption�Higher modulation capability

� Link budget

� 10-Gbps x 12-ch1060-nm parallel-optical module

Technical seminar at CERN, Sept. 23 2011 2H. Nasu/FITEL Phonics Laboratory, Furukawa Electric Co, Ltd.

� Performance data

� Future prospect

Performance trend (Super computer & Computer)(F

LOP

S)

100Peta

Next next next plan

250T

(bps

/mac

hine

)

There is correlation between computer performance and bandwidth.

Fujitsu “Kei” is No. 1 now, but no optical link

1Peta

10Tera

Computer for company

Earth simulator plan

Next generation plan

Next next plan

2.5T

25G

360TFLOPS

10PFLOPS

Technical seminar at CERN, Sept. 23 2011

1995 2000 2005 2010 2015 2020 2025

100Giga

Computer for research

Personal computer

SupercomputerRenewal of

conventional computer

250M

PSI symposium 2005 : Ministry of Education, Culture, Sports, Science and Technology

3H. Nasu/FITEL Phonics Laboratory, Furukawa Electric Co, Ltd.

Bandwidth trend of Backplane (Edge Router)

There will be high possibility of accelerating time plan in consideration for power consumption.consumption.

High speed interface (commercial base)

Electrical backplane

Optical backplane

Rou

ter b

ackp

lane

ban

d w

idth


Rou

ter b

ackp

lane

ban

d w

idth

100GbE standardizedNEDO’s project : Next generation High performance Network Device

New standard boost traffic and NW equipment bandwidth.


Data rate trend in server systems

Technical seminar at CERN, Sept. 23 2011 5

Forecast for server connection speed, supplied by Intel and Broadcom, indicates the migration from 1 to 10, then to 40 and 100 Gbit/s transmission is at hand

H. Nasu/FITEL Phonics Laboratory, Furukawa Electric Co, Ltd.

Power consumption in IT equipment� Power consumption trends

� Japan： 5 times, from 2006 to 2025� Worldwide： 9 times, from 2006 to 2025

⇒ CO2 emission-increase

Environmental issuePower consumption estimation

Green IT Project (Japan)•Power reduction target•Data center: ≥ 30％• NW router: ≥ 30％

International project

（日本）

Environmental issuePower consumption estimation(Japan)

TV

Server

NW Equipment

5X

12X


� Driving forward activities for power saving

Ministry of Economics, Trade and Industry, Green IT Project

International project•WSC / GAMS•Climate Savers•The Green Grid

6

NW Equipment


I/O power trend

� Power trend on optical and electrical inter face)

△ Commercial× Sample○ Research

Pow

er c

onsu

mpt

ion

(W/G

bps)

Power saving in optical transmission(Photonic integration)

Power saving in electrical transmission(Low voltage driving)

Electrical ElectricalElectrical

○ Research


Expectation and future perspective on optical interconnect (Technical roadmap of optical circuit packaging technology), p. 7 2010

7mW/Gbps(10Gbps x 12ch)

Pow

er c

onsu

mpt

ion

(W/

Furukawa Electric

year


Trend of Optical interconnection

2020

Optical printed board

Opt connector

LSI

Optical circuit board

Optical Module

Opt connector

Optical waveguide

Optical Fiber

LSI

board

Optical Fiber

Opt connector

Back plane

2012


Optical TransceiverLSI

Conventional optical interconnection

Optical module will be expected more small and high speed.Connector will be more high density.

Now


How dose electrical transmission distance affect to optical signal performance?

MSL=0mm MSL=400mm

RX output: Eye opening

no PE PE3

Optical engine

400mm

Input Input

200

250

Eye

ope

ning

(mV

)

50

60

70

Pow

er c

onsu

mpt

ion

grow

th r

ate

(%)

PE1 PE2 PE3

Eye opening at BER10-12

no PE PE3

•10Gbps, NRZ•12ch simultaneous operation

Eye opening and Power increase rate

Pow

er in

crea

se ra

te (

%)


0

50

100

150

0 100 200 300 400 500

MSL length(mm)

Eye

ope

ning

(mV

)

0

10

20

30

40

50

Pow

er c

onsu

mpt

ion

grow

th r

ate

(%)

no PEPower

Minimizing electrical connection between optical engine and LSI

Power saving

Pow

er in

crea

se ra

te (

%)


Requirements on optical interconnect

� Low power consumption� xx mW/Gbps

� High capacity� High speed, 10Gbps, 14Gbps, 25Gbps� High speed, 10Gbps, 14Gbps, 25Gbps� Number of multiplexed signals

� Longer transmission link� Covering the length of <300m� Very long distance in Enterprise: ~1km

� Low cost� $xx/Gbps


� $xx/m^2

� Higher reliability� Huge number of modules

Advantages of 1µm optical devices� InGaAs QW VCSEL

High differential gain

Wide bandwidth Low power

High power

High speed

Low band gap energy Low driving

voltage

Low power

Al free

Slow DLD

High reliability

Low current density

SPIE Proceedings, vol. 4649, pp.19-24, 2002.

Inhibiting Al oxidization

EBIC image after aging test


High sensitivity Low power drive of VCSEL

� InGaAs PIN-PD

25% increase compared with 850nm GaAs PD

Inhibiting DLD by IndiumInGaAs SQWGaAs SQW

PTL, vol. 2, no. 8, 1990


Power saving ability in TX� Low power operation of 1060-nm InGaAs QW VCSEL

� Clear eye openings� Error free transmission

Vpp I = 1.8 mAVpp

(mV)

150

230

I = 1.8 mA


A bias current of 1.8mA is sufficient for 10Gbps operation

J. B. Herou et. al, CLEO/QELS 2010, CWP3.

230

Low power operation by 1060nm VCSEL

� 1060nm VCSEL


S. Nakagawa, FOE-12, Photonix2011, Apr. 2011


Reliability of 1060nm VCSEL


S. Nakagawa, FOE-12, Fiber Optics Expo, Apr. 2011K. Takaki et.al, Photonic West. Jan. 2011


Power saving ability in TX

� TX power vs. VCSEL bias current

TXモジュールの消費電力8.0

25˚C 850nm VCSEL

Power consumption in TX

2.0

3.0

4.0

5.0

6.0

7.0

Pow

er c

onsu

mpt

ion

(mW

/Gbp

s)25˚C

80˚C

1060-nm VCSEL

850nm VCSEL


0.0

1.0

2.0

0 2 4 6 8 10

Pow

er c

onsu

mpt

ion

(mW

/Gbp

s)

VCSEL bias current (mA)

Higher modulation capability� 40Gbit/s direct modulation

NEC group

� 20Gbit/s parallel-optical module•12ch Transceiver

NEC group

T. Anan et. al. International Symposium on VCSELs and Integrated Photonics, E-3, 2007


K. Kurata, OFC2010, OThS3. K. Yashilki et. al., ICSJ2010, 19-3

•12ch Transceiver•20Gbit/s, PRBS 27-1•50m of GI50 MMF•Error free transmission•Minimum sensitivity: <-8.6dB at 10-12

•Crosstalk penalty: 4dB

1µm VCSEL (TU Berlin)� 980nm VCSEL


A. Mutig, OIDA Workshop, Apr. 2011


Advantages of 1µm optical link�Parameters

Items Parameters 1060nm 850nm

RX:PD Sensitivity

0.75A/WInGaAs

0.6A/WGaAs

Transmission loss 0.95dB/km 2.09dB/km

*1. IEC60925-1 2001, eye-safety class1.

4

pena

lty(d

B)

5Measured (1060nm)

Calculation (1060nm)

Calculation (850nm)4

5 Bit rate: 10Gbps OM3

OM22000MHz·km

Condition:Fiberbandwidth=5000MHz.km

Fiber optics

Transmission loss 0.95dB/km 2.09dB/km

Chromatic dispersion -34.2ps/nm/km -90.42ps/nm/km

TX:Eye safety

Maximum output power

+1.5dBmClass 1

-2.2dBmClass 1


0

1

2

3

0300 600 900

Transmission distance (m)

Incr

ease

ofpo

wer

pena

lty

3

2

1

01200

850nm 1060nm 1300nm

500MHz·km

Conventional OM2 applicable Low cost

Longer distance


Fiber transmission� Conventional OM-2 and OM-3 MMFs

� 1060-nm optimized MMF


OM2:Penalty <2dB up to 300mMax. 300m recommendation

OM3:Penalty ~4dB at 300mMax. 150m recommendation

1060-nm MMFPenalty ~3dB at 1000mPotential 300m or beyond

Received power (dBm) Received power (dBm) Received power (dBm)

Modal bandwidth� Power penalty as a function of transmission distance

� Bit rate: 10Gbps� Calculated by IEEE 802.3z link model spread sheet� Limited laser modes (1060-nm VCSEL)� Modal bandwidth is measured with frequency sweeping method� Modal bandwidth is measured with frequency sweeping method

2

3

4

5

6

Pow

er p

ena

lty (

dB

)

OM2OM31060nm MMFOM-2 simulationOM-3 simulation1060nm MMF simulation 850 nm (1) 1060 nm (2) 1300 nm (1)

2262 (OFL)2612 (LLM)1094 (OFL)1741 (LLM)4318 (OFL)

MMF typeModal bandwidth (MHz×km)

OM-2 790 1602

OM-3 4509 708

1060-nm MMF - -

Modal bandwidth


0

1

2

0 200 400 600 800 1000

Transmission distance (m)

Pow

er p

ena

lty (

dB

)

4318 (OFL)5433 (LLM)

1060-nm MMF - -

Note 1: Fiber bandwidth is calculated from DMD dataNote 2: Measured by frequency sweeping method

JIS C 6824, Aug. 1997.

OFL: Overfilled launchLLM: Limited laser modes

25Gbps optical link� Power penalty as a function of transmission distance

� Bit rate: 25Gbps� Receiver bandwidth: 18.75GHz� MMF bandwidth: 4700MHz.km (OM4 level)� Tr/Tf(20%-80%)=16ps� Tr/Tf(20%-80%)=16ps� Spectral linewidth: 0.45nm, 0.65nm

3

4

5

6

Pow

er p

enal

ty (d

B)

850nm

1060nm

100m 300m

Calculated by IEEE 802.3z link model spread sheet


0

1

2

0 0.1 0.2 0.3 0.4

Transmission distance (km)

Pow

er p

enal

ty (d

B)

0.45nm 850nm

0.45nm 1060nm

0.65nm 850nm

0.65nm 1060nm

Scalability to the future� Coarse wavelength division multiplexing (CWDM)

� Capability of selecting lasing wavelength� Wide range of wavelength sensitivity

MAUI project: parallel multiwavelength optical subassemblies (PMOSAs)

Cost reduction?

MAUI project: parallel multiwavelength optical subassemblies (PMOSAs)


LEOS2005, TuW1, Mar. 2005, JLT vol. 22, no. 9, p.2043 2004, ECTC, p.1027 2005.6.6mW/Gbit/s: 10.42Gbit/s x 48ch

Scalability to the future� Attenuation in polymer waveguides

� Poly (methyl methacrylate) (PMMA)� Not available

� Perdeuterated (PD) polymer� Available 2500

3000

3500

4000

4500

5000

PMMA base

PD polymer base

PF polymer base

1060nm

� Available

� Perfluorinated (PF) polymer� Available

� Applied to silicon photonics� 1060nm is in the transmittance window of Silicon

0

500

1000

1500

2000

2500

0.5 0.6 0.7 0.8 0.9 1.1 1.2 1.3 1.4Wavelength (µm)

1.0

T. Ishigure et. al, Science and Technology of Polymer and Advanced Materials, Plenum Press, New York, 1998

PCB

Polymer waveguide

VCSEL

Lens


� 1060nm is in the transmittance window of Silicon


10Gbit/s x 12ch optical engine� Optical pluggable and pigtailed engines

Heat sinkPigtailed90º-angled connector

Optical pluggable

21mm 21.7mm

Pluggable socketBW > 10GHz

Module 13X13Xt3.4mm

Module

Pluggable socket-1

0

-10

0


18mm18mm

-5

-4

-3

-2

0 2 4 6 8 10

Frequecncy (GHz)

S21 (dB

)

-50

-40

-30

-20

S11 (dB

)

S21S11


12.5Gbit/s x 12ch x 4� High-density optical pluggable solution

� 600Gbps mezzanine card


Parallel-optical engines

� 10Gbps × 12ch parallel-optical engine� 1060-nm VCSEL array，InGaAs PD array� BiCMOS LDD/TIA

� Electrical interface: pluggable socket

Heat sink

� Electrical interface: pluggable socket� Capability of replacing optical modules� Wide band width >10GHz

� Mechanical size:� Module: 13 × 13 × 3.4 mm(not to include pigtailed fiber)

� Socket: 21.7 × 21 × 13.7 mm

� Performance

21mm 21.7mm

Module


� Performance� Power consumption：：：： <10mW/Gbps� Operating case temperature 0~70°C

� Transmission： 120Gbps error free

Pluggable socket:BW > 10GHz

Module structure�Schematic view

Metal coverVD/TIAMicrolens

12-ch fiber ribbon

Thermal dissipation

-6

-3

0

SD

D21

(dB

)

-20

-15

-10

-5

0

SD

D11

(dB

)

RF pathDifferential transmission lines

12ch VCSEL/PD array

MT ferrule

Multi-layer ceramic substrate

S-parameter (EM simulation)

92 LGA


-15

-12

-9

0 5 10 15 20

Frequency(GHz)

SD

D21

(dB

)

-50

-45

-40

-35

-30

-25

SD

D11

(dB

)

DB(|S(2,1)|) : Spara_ESA

DB(|S(1,1)|) : Spara_ESA

SDD21: >-3dB at 0-10GHz>-5dB at 0-20GHz

SDD11: <-15dB at 0-20GHz

Electrical-pluggable interface

S-parameters

� Capability of module replacement� System maintenance� Repeatability of module installation

� Wide bandwidth: >10GHz

Cross sectional drawing

-3

-2

-1

0

S21

(dB

)

-30

-20

-10

0

S11

(dB

)

S-parameters� Wide bandwidth: >10GHz

Parallel-optical module


-5

-4

0 2 4 6 8 10

Frequecncy (GHz)

-50

-40S21S11

Electrical pluggable socket

Spring pin

Eye diagrams

� TX output and RX output

15°C 25°C 50°C 80°CTX TX output

RX output


Monitor channel: Ch 7Case temperature: 25~80°CBias current: 4mA, Optical power: -4.0dBm, Extinction ratio : 4.5dBTr/Tf: (TX output) 31.6ps/47.2ps,

(RX output) 36.0ps/37.6ps

BER performance� BER measurement

� 10Gbps × 12ch simultaneous transmissionOver operating case temperature

(Back to back) Transmission in MMF of 300m

BE

R

80℃

50℃

25℃

15℃

10-4

10-6

10-8

BE

R

Back to back

300m10-4

10-6

10-8


-18 -16 -14 -12 -10 -8 -6 -4 -2 0 Received optical power(dBm)

10-8

10-10

10-12

-18 -16 -14 -12 -10 -8 -6

Received optical power (dBm)

10-8

10-10

10-12

Minimum sensitivity at 25°C: -10.2dBm Power penalty: 0.6dB

Optical link power� 1060nm 12ch x 10.315Gbit/s optical link

� Tc=25°C: 5.9mW/Gbit/s� Tc=70°C: 6.4 mW/Gbit/s

6.4mW/Gbit/s

Minimum sensitivity: <-12dBm BER=1012

2

3

4

5

6

7

8

-16

-15

-14

-13

-12

-11

-10

Pow

er c

onsu

mpt

ion(

mW

/Gbp

s)

Sen

sitiv

ity(d

Bm

)

ch1

ch2

ch3

ch4

ch5

ch6

ch7

ch8

ch9

5.9mW/Gbit/s

6.4mW/Gbit/s


0

1

2

-18

-17

-16

0 20 40 60 80 Pow

er c

onsu

mpt

ion(

mW

/Gbp

s)

Sen

sitiv

ity(d

Bm

)

Case temprature(deg.C)

ch9

ch10

ch11

ch12

average

PC


Summary� Technical trends in data centers and optical interconnects are

described.� Advantages of 1-µm optical inter connects

� Low power consumptionHigher modulation capability � Higher modulation capability

� Longer transmission distance� Low cost solution with conventional OM-2 fibers� High reliability with InGaAs devices

� Expansivity of 1-µm optical inter connects� Usage of polymer waveguide� Silicon photonics� Coarse wavelength division multiplexing (CWDM)


� Coarse wavelength division multiplexing (CWDM)� 10-Gbps x 12-channel 1060-nm parallel-optical modules

� Size: 13mm x 13mm x 3.4 mm� Very Low power: <7mW/Gbps (Tc: 15°C to 80°C)� Electrical-pluggable socket interface� Very low power 7.0mW/Gbps over operating case temperature

Future perspective� Higher speed >25Gbps

� High speed devices VCSEL, PD, CMOS (Silicon) Photonics�Argument on wavelength: expectation on 1µm wavelength

� Electrical wiring： Wideband wiring, Crosstalk suppression� Bandwidth control： Equalization, Emphasis� Bandwidth control： Equalization, Emphasis

� Optical waveguide� Polymer waveguide

�Loss, Bandwidth�Optical coupling

� MMF�Bandwidth (Refractive index profile, Core diameter)

ECOC2010, Tu4G3, Sept. 2010.

Terabus Project


� High-density� Small optical engine� 3D integration, CMOS Photonics

� Mounting technology� Electrical pluggable� Permanent mounting

33

ECOC2010, Tu4G3, Sept. 2010.


Thank you!


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