JOURNAL OF LIGHTWAVE TECHNOLOGY, VOL. 24, NO. 8, AUGUST 2006 3195
A High Electromagnetic Immunity Plastic Composite
Package for a 10-Gb/s Optical Transceiver Module
Tzong-Lin Wu, Senior Member, IEEE, Min-Ching Lin, Cheng-Wei Lin, Wern-Shiang Jou,
Tien-Tsorng Shih, and Wood-Hi Cheng, Senior Member, IEEE, Member, OSA
Abstract—A high electromagnetic immunity and low-cost
plas-tic package for a 10-Gb/s opplas-tical transceiver module is developed
by using a woven carbon-fiber epoxy composite (WCEC). The
WCEC package with a thickness of 1.0 mm and 4.8% carbon fiber
has a shielding effectiveness (SE) performance of 60 dB at 10 GHz
as the package is grounded to the system ground, and the SE
can reach approximately 38 dB for the realistic packaged module
operated at 10 Gb/s. In addition, the excellent electromagnetic
im-munity of the package is demonstrated by the eye patterns and the
bit-error-rate (BER) test. Under the interference of the radiated
noise, the package housing significantly improves the jitter and
mask margin performance of the 10-Gb/s signals. Compared with
an unpackaged module, it is found that over 4 dB of optical power
can be gained to keep the BER at 10
−12for the packaged optical
transceiver modules. This proposed package is suitable for use
in low-cost 10-Gb/s lightwave transmission systems with excellent
electromagnetic susceptibility (EMS) performance.
Index Terms—Electromagnetic immunity, electromagnetic
sus-ceptibility (EMS), shielding effectiveness (SE), woven continuous
carbon-fiber composite, 10-Gb/s optical transceiver module.
I. I
NTRODUCTIONT
HE WIDESPREAD deployment of low-cost and
high-speed optical access networks for fiber-to-the-home
(FTTH) applications will necessitate a considerable reduction
in the cost of key components such as optical transceiver
modules to operate at higher transmission rates. The
high-speed driving and receiving electronic circuits are designed and
integrated with the optical components in a standard 1
× 9 type
small-form-factor packages or a 2
× 9 package [1]–[4].
Be-cause the trend of high-speed electronics is low voltage and
low power, the electromagnetic susceptibility (EMS) or
elec-tromagnetic immunity of the optical transceiver modules to
the electromagnetic interference (EMI) is becoming one of the
major concerns to maintain good signal quality of transmission
rates over 10 Gb/s [5], [6]. Designing high electromagnetic
shielding package/housing is a good solution to improve the
immunity performance of the optical transceiver modules. It is
well known that metallic housings provide excellent shielding
Manuscript received July 4, 2005; revised January 14, 2006.
T.-L. Wu is with the Department of Electrical Engineering and the Graduate Institute of Communication Engineering, National Taiwan University, Taipei 106, Taiwan, R.O.C. (e-mail: wtl@cc.ee.mtu.edu.tw).
M.-C. Lin, C.-W. Lin, and W.-H. Cheng are with the Institute of Electro-Optical Engineering, National Sun Yat-sen University, Kaohsiung 804, Taiwan, R.O.C.
W.-S. Jou and T.-T. Shih are with the Department of Mold and Die Engi-neering, National Kaohsiung University of Applied Science, Kaohsiung 807, Taiwan, R.O.C.
Digital Object Identifier 10.1109/JLT.2006.876345
effectiveness (SE). However, due to its low cost and
ease-of-manufacturing requirement, the plastic composite package has
been considered to be one of the major choices of fabricating
optical transceiver module package for use in FTTH
applica-tions [7]–[10].
Plastics alone are inherently transparent to electromagnetic
(EM) radiation and provide no shielding against radiated
in-terference. To improve the EM shielding for the plastic
pack-aging, electronic conductive properties have to be added into
the plastic hosts for adequate EM shielding. The currently
available techniques for preventing EMI include conductive
sprays, conductive fillers, zinc-arc spraying, electroplating or
electrolysis plating on the housing surfaces, modifications of
electrical properties during the molding stage, and other
metal-lization processes [11], [12]. Recently, several types of plastic
composite packages for the optical transceiver modules with
an effective EM shielding ability have been proposed. There
are nylon reinforced with short carbon fiber [1], liquid crystal
polymer (LCP) reinforced with long carbon fiber [2], and epoxy
composite with carbon fibers [2], [8]. Although these plastic
composite packages perform good SE, two drawbacks are seen.
One is that the pervious package needs a composite with a high
percentage of carbon fibers (over 25%). It will significantly
increase the cost because carbon fiber dominantly decides the
cost of the composite material. The other is that these packages
are developed in the application with a transmission rate not
higher than 2.5 Gb/s. With the trend of high-speed optical
communication, it is essential to develop a low-cost plastic
package with high SE and EMS performance at a frequency
range of 10 GHz or above.
This paper presents a high electromagnetic immunity and
low-cost plastic composite package for the optical transceiver
module operating at 10 Gb/s by employing the woven
carbon-fiber epoxy composite (WCEC). By weaving the continuous
carbon fiber in a balanced twill structure (BTS) with excellent
conductive networks, the SE of the package housing can be
significantly increased while keeping a very low weight
per-centage of carbon fiber at 10 GHz. The main difference of the
BTS-based WCEC from those previous composites is the use
of long carbon fiber with multiple contacts to weave the
fiber-conducting networks. It provides more continuous path of the
conducting current induced by the electromagnetic wave inside
the WCEC and thus enhances the SE performance.
The succeeding sections of this paper are organized as
fol-lows. Section II describes the fabrications of plastic composites
and plastic optical transceiver modules with transmission rates
of 10 Gb/s. The measurement results of the SE for the plastic
3200 JOURNAL OF LIGHTWAVE TECHNOLOGY, VOL. 24, NO. 8, AUGUST 2006
Fig. 9. BER versus the received optical power for three different cases, namely 1) unpackaged module without radiated interference (case A); 2) unpackaged module with radiated interference (case B); and 3) packaged module with radiated interference (case C).
case C with the package housing, it is clearly seen that the
BER performance is significantly improved. The optical power
is approximately
−12.9 dBm for a BER of 10
−12. Comparing
between cases B and C, it is found that the proposed WCEC
package significantly increases the electromagnetic immunity
to the radiated interference with an optical power gain of
approximately 4.1 dB at BER 10
−12.
V. C
ONCLUSIONBased on the WCEC, this paper proposes a high EMS
perfor-mance (or high electromagnetic immunity) and low-cost plastic
composite package for the 10-Gb/s optical transceiver module.
By weaving the continuous carbon fiber in a BTS with excellent
conductive networks, the package housing performs excellent
shielding and electromagnetic immunity while keeping a very
low weight percentage of carbon fiber at 10 GHz. It is found
that the WCEC package with a thickness of 1.0 mm and 4.8%
carbon fiber can have an SE performance of approximately
60 dB at 10 GHz as the package is grounded to the system
ground. The SE can also reach approximately 38 dB for the
realistic packaged module operated at 10 Gb/s. In addition, the
excellent electromagnetic immunity or EMS performance of
the package is demonstrated by the eye diagrams and the
BER test. Under the strongly radiated interference, the package
housing significantly improves the jitter and mask margin of the
10-Gb/s eye diagrams. Compared with the unpackaged module,
it is also found that an optical power over 4 dB can be gained
to keep the BER at 10
−12. To the best of our knowledge, it
is the first plastic composite package developed for a 10-Gb/s
optical communication module with low-cost and high EMS
performance.
R
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Tzong-Lin Wu (S’93–M’99–SM’04) received the
B.S. and Ph.D. degrees in electrical engineering from the National Taiwan University, Taipei, Taiwan, R.O.C., in 1991 and 1995, respectively.
From 1995 to 1996, he was a Senior Engineer with Microelectronics Technology, Inc., Hsinchu, Taiwan. From 1996 to 1998, he was with the Cen-tral Research Institute, Tatung Company, Taipei, where he was involved with the analysis and mea-surement of electromagnetic compatibility (EMC)/ electromagnetic interference (EMI) problems of high-speed digital systems. From 1998 to 2005, he was with the Department of Electrical Engineering, National Sun Yat-sen University (NSYSU), Kaohsiung, Taiwan. He is currently an Associate Professor with the Department of Elec-trical Engineering, National Taiwan University. His research interests include modeling and measurement for EMC/EMI and signal integrity in high-speed digital/optical systems and design and analysis of fiber-optic components.
Dr. Wu is a member of the Chinese Institute of Electrical Engineers. He received the Excellent Research Award and Excellent Advisor Award from NSYSU in 2000 and 2003, respectively, the Outstanding Young Engineers Award from the Chinese Institute of Electrical Engineers in 2002, and the Wu Ta-You Memorial Award from the National Science Council in 2005. He was also listed in Marquis’ Who’s Who in the World in 2001.
WU etal.: HIGH ELECTROMAGNETIC IMMUNITY COMPOSITE PACKAGE FOR 10-Gb/s OPTICAL TRANSCEIVER MODULE 3201
Min-Ching Lin was born in Taipei, Taiwan, R.O.C.,
on August 25, 1979. He received the B.S. degree in electrical engineering from Yuan-Ze University, Taoyuan, Taiwan, in 2001 and the M.S. degree in electrooptical engineering from the National Sun Yat-sen University, Kaohsiung, Taiwan, in 2003. He is currently working toward the Ph.D. degree in electrooptical engineering at the National Sun Yat-sen University.
His research interests include optoelectronic pack-aging and radio frequency circuit design for telecom-munication applications.
Tien-Tsorng Shih was born in Taiwan, R.O.C., in
1965. He received the B.S. and Ph.D. degrees in electrical engineering from the National Chiao Tung University, Hsinchu, Taiwan, in 1986 and 1991, re-spectively.
In 1991, he joined Telecommunication Laborato-ries, Taiwan, as a Research Associate. From 1996 to 2000, he was a Project Manager with Chunghwa Telecommunication Laboratories, Taipei, Taiwan. In 2000, he founded Infomax Optical Technology Cor-poration and was the CEO from 2000 to 2003. He is currently an Assistant Professor with the Department of Electronics Engineer-ing, National Kaohsiung University of Applied Science, Kaohsiung, Taiwan. His main research interests include the theoretical study of optical waveguides and III-V optoelectronic devices, fabrication of laser diodes, photodiodes, and planar lightwave circuits, packaging technology for optoelectronic devices, transceiver modules, and transmission technologies for the fiber optics com-munication applications.
Wood-Hi Cheng (M’95–A’96–SM’00) was born
in Changhua, Taiwan, R.O.C., on June 3, 1944. He received the Ph.D. degree in physics from the Oklahoma State University, Stillwater, in 1978.
From 1978 to 1980, he was a Research Asso-ciate with Telecommunication Laboratories, Taiwan. From 1980 to 1984, he was a Research Engineer with General Optronics, Edison, NJ. From 1984 to 1991, he was a Principal Design Engineer with Rockwell International, Newbury Park, CA. From 1991 to 1994, he was an Optoelectronic Packaging Manager with Tacan Corporation, Carlsbad, CA. He is currently a Professor with the Institute of Electro-Optical Engineering, National Sun Yat-sen University, Kaoshiung, Taiwan. He served as a Consultant for Chunghwa Telecom Labora-tories, Optoelectronics and System LaboraLabora-tories, and Chung-Shan Institute of Science and Technology, all in Taiwan. His research and development activities have been focused on the design and fabrication of high-speed semiconductor lasers for lightwave communications, highly efficient light coupling from lasers into fibers, fiber couplers, characterization of III–V semiconductor ma-terials, and optoelectronic packaging. His current research interests are the design, fabrication, and finite-element-method analysis for laser module pack-aging, high-speed laser module packaging for digital lightwave systems, fab-rication of high-density wavelength-division-multiplexing components, and novel materials for electromagnetic shielding.
Dr. Cheng is a member of the Optical Society of America (OSA) and the Photonics Society of Chinese-Americans. He served as a Chair for the IEEE Lasers and Electro-Optics Society, Taipei Chapter, from 1999 to 2000, and currently serves as a Vice-Chair for the OSA, Taipei Chapter.
Photographs and biographies of co-authors Cheng-Wei Lin and
