1

Electromagnetic Shielding of Plastic Packaging in Cost-Effective Optical

Transceiver Modules

Wood-Hi Cheng1, Tzong-Lin Wu2, Wern -Shiarng Jou3

1. Institute of Electro-Optical Engineering, National Sun Yat-Sen University, Kaohsiung, Taiwan.

2. Department of Electrical Engineering, National Sun Yat-sen University, Kaohsiung 80424, Taiwan

3. Department of Mold and Die Engineering, National Kaohsiung University of Applied Sciences, Kaohsiung, Taiwan

2

Objective of Study

To develop the plastic optical transceiver modules with low cost and low electromagnetic interference (EMI) for use in Gigabit Ethernet or fiber to the home (FTTH) lightwave communication systems

3

Outline1. Motivation

2. Fabrication and Shielding Performance of Plastic Composites with Discontinuous Carbon Fiber Fillers

3. Fabrication and Shielding Performance of Plastic Composites with Continuous Carbon Fibers

4. Fabrication and Shielding Performance of Hallow Carbon Nanocapules

5. Comparison of Fabrication and Shielding Performance for Plastic Composites and Plastic Optical Transceiver Modules

6. Conclusion

4

Low Cost Laser Module Packages

10

102

103

104

1980 1985 1990 1995 2000 2005

Pric

e (S

.U. d

olla

rs)

PigtailPigtail

connectorized Connectorized

Box-type Box-type Coaxial-type

Coaxial-type

Automated assembly

DIP Butterfly Coaxial: cylindricalBox:

YearTelecom Cooled

Telecom & Datacom Uncooled

5

Transceiver Module Market

>10Gb/s 1%

<2.5Gb/s 9%

<1.25Gb/s 16%

<622Mb/s 7%

<155Mb/s 67%

Source: Fuji Chimera (2002)

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Optical Transceiver ModuleData Rate :155Mb/s 1.25Gb/s 2.5Gb/s

1X9 Type

1.2 cm

5.7 cm 3.1 cm

Small Form Factor Pluggable (SFP)

55.72mm

13.3 mm

Height = 8.55 mm

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Frame of Transceiver Module

8

Techniques for plastic EM shielding

• Conductive sprays • Conductive fillers • Zinc-arc spraying • Electro-plating or electrolysis-plating on housing

surfaces • Modifications of electrical properties during the

molding stage • Metallization processes

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Conductive fillers for EM shielding

• Metal particles • Metal flakes • Stainless fiber • Graphitized carbon particles • Graphitized carbon fibers • Metal-coated glass • Carbon fibers

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Fabrication of plastic composites

1.Twin–Screw Extruder

Plastic materials

Carbon fibers

Plastic composites

Injection Molding

Process:

Injection

Fiber Direction

3.specimen2.Injection-Molded Machine

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Metallographic

LCP (25% Carbon Fiber)

LCP :with 25% carbon fiberorientation uniform

Nylon :with 25% carbon fiberorientation random

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Measurement Setup

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LCP and Nylon Composites

0

20

40

60

80

0 500 1000 1500Frequency (MHz)

Shie

ldin

g ef

fect

iven

ess (

dB)

LCP (uniform)

Nylon (random)

50 dB 55 dB

1.25GHz155MHz

10dB

45dB

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Woven Continuous Carbon Fiber Fabrics

Advantages：1. continuous carbon fiber 2. complete conductive networks3. easy fabrication and low cost

Polymer composites Fabrics

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Fabrication of WCC Fabrics

Different Weave Methods Epoxy

Compression molding machine

Test samples

Plain Balanced Twill Uni-direction

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Fabrication of HCNCs Composites

HCNCs Epoxy

Hydraulic machine Test samples

133mm

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Metallographic

(a) Nylon (b) LCP

(d) HCNC(c) WCCF

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Comparison of SE Performance of Nylon, LCP, WCCF and HCNCs Composites

0

10

20

3040

50

60

70

0 1000 2000 3000Frequency(MHz)

Shie

ldin

g E

ffec

tiven

ess(

dB)

Weavon Carbon FiberLCP+20% CFnylon+20% CFHCNCs

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Anechoic Chamber

Antenna

Wooden Table

Chamber volume = 7m x 4m x 3m

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S.E. measurement for near-field monopole-type source in a fully anechoic

EMC chamber

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Comparison of SE performance of realistic housings fabricated by HCNCs composites

0

10

20

30

40

50

0 1000 2000 3000 4000Frequency(MHz)

Shie

ldin

g E

ffec

tive

ness

(dB

)Weavon Carbon FiberLCP CompositeNylon CompositeHCNCs

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Comparison of cost, and shielding performance of plastic composites

9

4

83

83

Total Weight

( g )

41

0.06

1.91

0.96

0.5

0.5

3

3

Thickness of Sample

(mm)

40~507Carbon

Nanocaplsule( 5.88 )

Epoxy

( 8.8 x 10-3 )

Carbon Nanocaplsule

40~502Carbon Fiber

( 2.3 x 10-2 )

Epoxy

( 8.8 x 10-3 )

Weavon Carbon Fiber

40~5016.6Carbon Fiber

( 2.3 x 10-2 )

LCP

( 2.3 x 10-2 )

LCP Composite

40~5016.6Carbon Fiber

( 2.3 x 10-2 )

Nylon-66

( 8.8 x 10-3 )

Nylon Composite

SE (dB)

Cost of Sample

(US)

Weight of Filler (g)

Filler(Cost/g)

Material(Cost/g)

Sample

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Measurement setup of the radiated emission for the optical transceiver

module in normal operation

Pattern Generator

Spectrum Analyzer

Signal Analyzer

3m

Shielding Radiation

Fiber

SCSignal

AnalyzerPattern

Generator

Package

Holes(7mm)

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Comparison of SE performance of optical transceiver modules at 1.25 GHz and 2.5 GHz fabricated by nylon,

LCP, WCCF and HCNCs composites

0

10

20

30

40

0 1 2 3 4Frequcency(GHz)

Shie

ldin

g E

ffec

tive

ness

(dB

)Weavon Carbon FiberLCP CompositeNylon CompositeHCNCs

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Eye Diagram of 2.5Gb/s Transmitter

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Comparison of cost, and shielding performance of optical transceiver modules

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2.5

51.5

51.5

Total Weight

( g )

35

0.04

1.18

0.64

0.5

0.5

3

3

Thickness of Sample

(mm)

126Carbon

Nanocaplsule( 5.88 )

Epoxy

( 8.8 x 10-3 )

Carbon Nanocaplsule

241.24Carbon Fiber

( 2.3 x 10-2 )

Epoxy

( 8.8 x 10-3 )

Weavon Carbon Fiber

1712.8Carbon Fiber

( 2.3 x 10-2 )

LCP

( 2.3 x 10-2 )

LCP Composite

1512.8Carbon Fiber

( 2.3 x 10-2 )

Nylon-66

( 8.8 x 10-3 )

Nylon Composite

SE (dB)

Cost of Sample

(US)

Weight of Filler (g)

Filler(Cost/g)

Material(Cost/g)

Sample

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ConclusionLow-cost optical transceiver modules with transmission rates of 155Mb/s, 1.25Gb/s, and 2.5Gb/s were successfully fabricated to investigate the EM shielding ability.

• The LCP composites perform better SE than the nylon66. This is the LCP polymer chains have higher ordering structure under both melting and solid state.

• By comparison of cost, weight and shielding performance for optical transceiver modules fabricated by the housings of nylon, LCP, WCCF and HCNCs composites, the WCCF composite showed lower cost, lighter weight and higher EM shielding than the other types of composites.

• Due to the fact that the electronic and mechanical properties of HCNCs composites are remarkable, future research and development may push to develop the low cost and low EMI optical transceiver modules using nanoscale HCNCs.

• The packaged plastic optical transceiver modules with low cost and low EMI are suitable for use in Gigabit Ethernet or fiber to the home lightwave (FTTH) communication systems.

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100~160Gb/s SYSTEM

.

DEVICE

PACKAGE

Thank for your attention

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