100GE over SMF Using 4x10G DMLand 4x25Gb/s Linear Equalizers

100GE over SMF Using 4x10G DMLand 4x25Gb/s Linear Equalizers

Winston Way, Yuling Zhuang, Jerry Liu, NeoPhotonics

Ali Ghiasi, Fred Tang, Broadcom

Next Gen 100GbE Optical SG, Newport Beach, January 2012

• Kai Cui, Huawei

• Frank Chang, Vitesse

• Ahmet Balcioglu, Hittite

SupportersSupporters

1

IntroductionIntroduction

• The feasibility of using uncooled 1300nm CWDM 10G

DML and 25G equalizer to carry 25Gb/s data is explored

• Potential for 4x25Gb/s short reach SMF (<2km)

application

• Simple, low cost, low power consumption

• Reuse most of the components from today’s 40GBASE-LR4 and

100GBASE-LR4

– CWDM mux & demux (20nm spacing)

– 4x25Gb/s ROSAs

– 4x25Gb/s CDRs

• Possible half re-timed at TX only, or un-retimed

Advantages of the New ApproachAdvantages of the New Approach

• Leverage the potential volume use of 25Gb/s equalizers, which will be

integrated in a CDR or a gearbox, and will be used for MMF and Cu

• Can fit into small modules such as QSFP or CFP2

• Wavelengths compatible with 40G-LR4 for dual speed operations up to

2 km

3

4x

10G DML

uncooled

4x

25G PD

4x

25G CDR

4x

25G EQ

+ CDR

4x

10G DML

uncooled

4x

25G PD

4x

25G LDD

+CDROR

(EQ/CDR in external

gearbox)

OR

4x

10G DML

uncooled

4x

25G PD

4x

25G LDD

4x

25G EQ/

CDR in GB

Experimental & Simulation SetupExperimental & Simulation Setup

I

26GHz

Bias-T

25Gb/s Pulse

Pattern

Generator

500mVpp(emulate CDR 10Gb/s

45ΩΩΩΩ

Adjustable

4

(emulate CDR

or gearbox

single-ended output)

25Gb/s

Receiver

10Gb/s

1270nm

DFB LD

Captured WaveformEqualizer WDP

Analysis

Adjustable

Attenuation

Eye Diagrams at Different Bias LevelsEye Diagrams at Different Bias Levels

I bias = 30 mA

3dB BW= 10.5 GHz

ER= 1.9dB

I bias = 40 mA

3dB BW= 11.1 GHz

ER= 1.3dB

5

I bias = 18 mA

3dB BW= 8.1 GHz

ER= 5.2dB

I bias = 20 mA

3dB BW= 8.9 GHz

ER= 4.0dB

1270nm 10G DML Frequency Response1270nm 10G DML Frequency Response

6

Calculated WDP for Measured Waveforms (PAlloc=5dB)Calculated WDP for Measured Waveforms (PAlloc=5dB)

4

6

8

10

12

WD

P (

dB

)

18mA 20mA 30mA 40mA

7

0

2

4

1FFE 4FFE

6FFE 6FFE_3DFE

1FFE_5DFE 14FFE_5DFE

• At low bias levels (18, 20mA), WDP for a realizable equalizer is >5dBo

• At high bias levels (30, 40mA), WDP for a realizable equalizer is <5dBo

• At high bias levels, WDP remains fairly constant (1FFE+5DFE, 6FFE+3DFE) within the received power range of 5.8dB

(channel insertion loss budget for 2km SMF is 4dB, which includes 2dB connector/splice loss)

-9.0

-6.0

-3.0

0.0

3.0

6.0

S2

1 (d

B)

S21 EO Response (Mitsubishi Laser1_COS14385)

Mitsubishi_80C_30mA

Mitsubishi_80C_40mA

AlGaInAs–InP 10Gbps DFB Lasers-High Bandwidth, High Temperature Operations

AlGaInAs–InP 10Gbps DFB Lasers-High Bandwidth, High Temperature Operations

80-degC

-30.0

-27.0

-24.0

-21.0

-18.0

-15.0

-12.0

0 2 4 6 8 10 12 14 16 18 20

S2

1 (d

B)

Frequency (GHz)

Mitsubishi_80C_50mA

Mitsubishi_80C_65mA

8

• Driver amplifiers: 3dB bandwidth > 19GHz

• 4x10G package: 3dB bandwidth > 17~18GHz

Electronic Components for 10GElectronic Components for 10G

9

• Technical feasibility of using 4x25G 1300nm CWDM DML and 4x25G linear

equalizer (to be integrated in a CDR) for short reach (<2km) SMF is studied via

experiment and simulation

• Due to the replacement of 25G DML or EML by a 10G DML, and the elimination

of 25G laser drivers, there will be a significant cost reduction

• This low cost and low power approach can use a small module such as QSFP

or CFP2

SummarySummary

or CFP2

10

Next StepsNext Steps

1. . Test packaged AlGaInAs–InP 10Gbps DFB Lasers at high

temperature through 2km SMF, with or without driver amps

2. Compare the performance differences between

un-retimed and re-timed configurations

Backup Slide

11

Extra Penalty Due to Smaller ERExtra Penalty Due to Smaller ER

100GE-2km

ER≥1.9dB

~3dB

12

100GE-LR4

ER≥4dB

0.47dB/km x (10km – 2km)= 3.76dB