Enabling Optical Technologies for Optical Ethernet · Enabling Optical Technologies for Optical Ethernet WOCC 2004 San Liang Lee Dept. of Electronic Engineering, and Center for Optoelectronic

Enabling Optical Technologies for Optical Ethernet

WOCC 2004

San Liang LeeDept. of Electronic Engineering, and

Center for Optoelectronic Science and Technology

National Taiwan University of Science and Technology

Optical Networks Laboratory

NTUST

2 2004/3/8 S.-L. Lee WOCC2004

Outline

• Optical Ethernet• Enabling Optical Technologies

– Optical Label Switches– Tunable Lasers– Wavelength Converters

• Fixed wavelength• Broadband• Multicast

• Conclusions


NTUST

3 2004/3/8 S.-L. Lee WOCC2004

Optical Ethernet

Optical LAN/WAN

DVD/R/RW

Wide-Band Optical Amplifier

Trunk line

DWDMC-band :1530-1564nmL-band : 1565-1620nm

Ethernet-basedMetro-Core

SplitAccess Line

Comm. Tower

TransportMetro/Access

Optical Submarine Cable

10GbE/GbE

10GbE/GbE

10GbE/GbE


NTUST

4 2004/3/8 S.-L. Lee WOCC2004

Ethernet over Optics

Before:• Ethernet was a LAN technology • SONET, ATM, and MPLS provide the necessary

traffic management and SLA verification capabilities for service provider networks

• Metro Ethernet are offered by service providers for– Ease of use– Low cost– Flexibility

• Extending beyond metro and across transport networks

Now:


NTUST

5 2004/3/8 S.-L. Lee WOCC2004

Metro Ethernet Must Ensure

• Low latency and jitter• Survivability: SONET-like, support multiple grades of

restoration, varying levels of priority, and optical layer automatic protection switching.

• Reach: Metro networks often span 100km or more. Today 40km reaches are being specified for 10-gigabit Ethernet

• Traffic and congestion management: ATM-like • Security• Standard: Metro Ethernet, and 10 GbE


NTUST

6 2004/3/8 S.-L. Lee WOCC2004

Why Optics?

• Huge carrier frequency (~200 THz)Large signal modulation bandwidth

• Huge transmission bandwidth (>60THz, wired)No need of spectral efficient codingSimple signal encoding/decoding, allow high speed

• Nearly perfect channel (fiber)Abundant in materialLow-loss, low dispersion, and no interference

• Short wavelength (~1µm)Small waveguide dimensionSmall antenna (laser and detector)


NTUST

7 2004/3/8 S.-L. Lee WOCC2004

Why Optics? (cont’)

• Additional dimension of signal encodingWavelength, frequency, time, codeAllow hierarchical data encodingAllow flexible bandwidth aggregation and management

• Fast switching???Propagating in light speed, not switching in light speedExcellent line speed. All optic devices work at the huge carrier frequency and has large bandwidthPhotons run faster, but electronics jump over shorter gatesUsually need electronic switching circuitsLack of optical computing and memoryNot necessarily rapidly switchable


NTUST

8 2004/3/8 S.-L. Lee WOCC2004

Optics for Ethernet

• 10 GbE transceivers (mature now!)• Agile modules: flexibility, fast switching• Data routing: label swapping, lambda switching• Performance monitoring: restoration and class of

service• Wavelength conversion: reduce # of wavelengths


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9 2004/3/8 S.-L. Lee WOCC2004

Label Switched Networks

UCSB AOLS project


NTUST

10 2004/3/8 S.-L. Lee WOCC2004

Optical Router in AOLS

Rx

Fast logic

DFB

XGMWC

2%

50%

On/OffFast Tunable laser

Fast table lookup

λ Select & New Label

50% XPMWC

/Filter

Fast wavelength tunable transmitter

Filter

Fast WavelengthTunable Laser Source

Wavelength Router

(Arrayed Waveguide Grating)

tt

t

t

t

WavelengthConverter


NTUST

11 2004/3/8 S.-L. Lee WOCC2004

NTUST Label-Switched Router: proposal• Encode the data and payload on different wavelengths• Allow for using low-cost lasers and wavelength converters

DI

HPWC

(2-section) Filter

0λI

Rx Headerprocess

Fast tunableLaser

FixedLaser

WC(FWM)

NewHeader

H’P’

GHz500'0 += λλ

H’ P' Pump 1 P HPump 2

FixedTunableλ

I: interleaver

Wavelength Router


NTUST

12 2004/3/8 S.-L. Lee WOCC2004

Fast Tunable Lasers for Data Routing

TEC

DBR laser

IgainITEC

DAC withcurrent out

Igrating

\ 12 bits

SRAM-basedwavelength

decoder

selectterface

Ultra-stablecurrentsource

Temperaturecontroller

m λs’WDMOptical Source

uP-based control unit

User Interface

Iphase

Circuit Spec.Rise/Fall time : 1.5nsCurrent range: 20mACurrent res.: 20uA

λsin


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13 2004/3/8 S.-L. Lee WOCC2004

DBR Lasers


NTUST

14 2004/3/8 S.-L. Lee WOCC2004

Wavelength Stability During Tuning

∆f<1GHz


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15 2004/3/8 S.-L. Lee WOCC2004

Tuning Characteristics

On ITU gridPre-aging

Post-aging

Ideal

Wav

elen

gth

Tuning mechanism

Mode hopping or

incomplete tuning

Tuning curve of a tunable laser varies with the aging process or temperature fluctuation.


NTUST

16 2004/3/8 S.-L. Lee WOCC2004

Channel Monitoring + λ-Locker

Tunable LD IsolatorBeamsplitter

Outputbeam

Power monitor (PD3) Waveplate

Multi-channel monitor (PD4) Linear polarizer

Lens

WavelengthlockerPD1

PD2 Etalon Lens

Heat sink

Isolator

Compact module

EtalonWaveplate

IsolatorPolarizer LensPD1

PD3

PD2Power: PD1Wavelength: PD3/PD2Channel: PD2/PD1


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17 2004/3/8 S.-L. Lee WOCC2004

Tunable Laser monitoring

Proper tuning Mode hopping and wavelength drift

0

0.5

1

1.5

2

0.02

0.04

0.06

0.08

0.1

0.12

0.14

0 20 40 60 80 100

PD1(mW) PD2(mW)PD3(mW)

PD

1 (m

W)

PD2, P

D3 (m

W)

T ime (s)

Ch5 drift = +0.01 nm

Mode hopping

Ch5 drift = -0.02 nmCh1

Ch2Ch1

Ch2Ch3

Ch4

Ch5 Ch5

0

0.5

1

1.5

2

0.02

0.04

0.06

0.08

0.1

0.12

0.14

0 20 40 60 80 100

10 ITU CHsITU=1540.56~1547.72 nm,

100 GHz spaced

PD

1 (m

W)

PD

2, PD

3 (mW

)T ime (s)

Ch2Ch1

Ch3Ch4

Ch5Ch6

Ch7

Ch8

Ch9

Ch10

PD2≠PD3 wavelength drift


NTUST

18 2004/3/8 S.-L. Lee WOCC2004

Two-Section DFB Lasers

• Use a thin shift layer to obtain stable single-λ output• Low-cost sources• Can be used for λ-conversion with fixed output λ

n-InP

p-InP

SCHMQWs

gratinglayer

shift layeretching stop


NTUST

19 2004/3/8 S.-L. Lee WOCC2004

Two-Section DFB Lasers (cont’)

0

5

10

15

20

25

30

0 20 40 60 80 100 120 140Injection current (mA)

SL:noSL=1:4 AR/AR

T=10oC

20

30

40

50

60

70

8085

-80

-70

-60

-50

-40

-30

-20

-10

1.56 1.564

0

100

200

300

400

1.555 1.56 1.565 1.57

Rel

ativ

e In

tens

ity (d

B)

Wavelength (µm)

T=5oC

10

20

30

40

50

60

70

80


NTUST

20 2004/3/8 S.-L. Lee WOCC2004

TS-DFB as Wavelength Converters

0

2

4

6

8

10

12

1545 1546 1547 1548 1549 1550

Extinction ratio to Input pumping wavelength

Extin

ctio

n ra

tio (d

B)

Input pumping wavelength (nm)


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21 2004/3/8 S.-L. Lee WOCC2004

Reshaping and ASE ImmunityInput

Output


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22 2004/3/8 S.-L. Lee WOCC2004

FWM-SOA Broadband Wavelength Converters

DFB-LDPs

PC OCSOA

ATT EDFAPIN FilterFilter

Assist beam

1480/1550MuxIsolator

PC

10Gb/sBERT

223-1 PRBS10Gb/s

OC

TL P1 TL P2

LiNbO3modulator

1480 nm

SOA

Pump1

Signal

ωs ωp1ω

Pump2

ωp2

Pump1

SignalConverted

ωsωp1ωcω

Pump2

ωp2

Assisted beam

1480nm

∆λ


NTUST

23 2004/3/8 S.-L. Lee WOCC2004

FWM-SOA Wavelength Converter (cont’)

-50

-45

-40

-35

-30

-25

-20

-15

-10

-5

0

-60 -50 -40 -30 -20 -10 0 10 20 30 40 50 60Wavelength conversion range (nm)

CE

(dB

)

10

15

20

25

30

35

40

45

50

55

60

SBR

(dB)

with assist beamw/o assist beam

SBR

CE

w/o A-beam

w/ A-beam


NTUST

24 2004/3/8 S.-L. Lee WOCC2004

Multicast Wavelength Converters

Wavelength Router

(Arrayed Waveguide Grating)

tt

t

t

t

WavelengthConverter

w/ same data

Wave 3 Wave 2Wave 1

Signal


NTUST

25 2004/3/8 S.-L. Lee WOCC2004

Summary

• Optics can provide Ethernet-based networks w/– More flexibility and re-configurability– Survivability– Fast data routing– Class of service– Multicast

• A label-switched router is proposed for best use of the strength of optics

• Optical technology can be cost-down further from integration and mass production


NTUST

26 2004/3/8 S.-L. Lee WOCC2004

Acknowledgment

• Contributors: – Chun-Liang Yang, Pei-Miin Gong, Rong Xuan, Ryan Chien,

Dar-Zu Hsu, Chih-Jen Wang, Pei-Ling Jiang

• Financial sponsors and collaborators :– National Science Council– Ministry of Education– Telecommunication Lab., Chunghwa Telecom– National Taiwan University– Luminent Inc., USA– CCL, ITRI

Documents

Enabling Optical Technologies for Optical Ethernet · Enabling Optical Technologies for Optical Ethernet WOCC 2004 San Liang Lee Dept. of Electronic Engineering, and Center for Optoelectronic