High-Performance and Low-Cost 10-Gb/s Bidirectional Optical Subassembly Modules

3488 JOURNAL OF LIGHTWAVE TECHNOLOGY, VOL. 25, NO. 11, NOVEMBER 2007

High-Performance and Low-Cost 10-Gb/s

Bidirectional Optical Subassembly Modules

Tien-Tsorng Shih, Min-Ching Lin, Pei-Hao Tseng, Chang-You Li, Tuan-Yu Hung,

Yi-Jen Chiu, Member, IEEE, and Wood-Hi Cheng, Senior Member, IEEE, Fellow, OSA

Abstract—High-performance and low-cost 10-Gb/s

bidirec-tional optical subassembly (BOSA) modules that are obtained

by adopting low-cost transistor outline (TO)-Can materials and

processes are proposed and demonstrated. The BOSA module

consists of an uncooled 1.3-µm distributed-feedback laser diode

and a 1.5-µm p-i-n/transimpedance amplifier receiver (Rx), which

integrate a 45

tilted thin-film wavelength-division multiplexing

filter to transmit a 1.3-µm light into the fiber and reflect a

1.55-µm light into the Rx. The matching resistor and low parasitic

inductance packages are applied with the TO-Can laser diode to

enable 10-Gb/s operation. A modulation bandwidth of 11.86 GHz

and an OC-192 eye diagram of a 19% mask margin are obtained

from the transmitter side. After a 10-km single-mode fiber (SMF)

transmission, the mask margin for the OC-192 eye diagram

de-creases to 11%. For the Rx, an OC-192 eye diagram of a 31%

mask margin is obtained under back-to-back connections. The

mask margin is maintained at 29% after a 10-km SMF

trans-mission. The measured crosstalk penalty is 0.9 dB at the Rx side.

These results indicate that the BOSA module is capable of a

10-Gb/s bidirectional transmission. This unique high-performance

10-Gb/s BOSA module not only demonstrates the feasibility of

a 10-Gb/s bidirectional transmission on an SMF for

fiber-to-the-home applications but also shows the low-cost possibility to ensure

the success of next-generation 10-Gb/s access networks.

Index Terms—Bidirectional optical subassembly (BOSA), fiber

to the home (FTTH), low cost, OC-192.

I. I

T

HE HIGH bandwidth of optical links has created a wide

variety of applications in commercial, industrial, and

mil-itary areas. For optical communication systems, the optical

sig-nal usually transmits in a single direction along the optical fiber.

To utilize the bandwidth of the optical fiber more efficiently,

a bidirectional transmission technology over a single fiber has

been constructively developed and widely installed in

fiber-to-the-home (FTTH) networks.

Manuscript received February 13, 2007; revised August 13, 2007. This work was supported in part by the National Science Council, Taiwan, R.O.C., under Contract NSC95-2215-E-110-089 and in part by the Ministry of Education under the Aim for the Top University Plan.

T.-T. Shih is with the Department of Electronics Engineering, National Kaohsiung University of Applied Sciences, Kaohsiung 80778, Taiwan, R.O.C. (e-mail: [email protected]).

M.-C. Lin, P.-H. Tseng, Y.-J. Chiu, and W.-H. Cheng are with the Institute of Electro-Optical Engineering, National Sun Yat-Sen University, Kaohsiung 80424, Taiwan, R.O.C. (e-mail: [email protected]. edu.tw; [email protected]; [email protected]; [email protected]).

C.-Y. Li and T.-Y. Hung are with APAC Optoelectronics Inc., Hsinchu 303, Taiwan, R.O.C. (e-mail: [email protected]; hank.hung@apacoe. com.tw).

Digital Object Identifier 10.1109/JLT.2007.907786

Recently, bidirectional optical subassembly (BOSA)

mod-ules for bidirectional transmission have been extensively

de-veloped [1]–[11]. Some researchers adopted planar lightwave

circuit (PLC) techniques to assemble the BOSA modules

[1]–[7]. The process of the BOSA modules using the PLC

technique is different when compared with the commercial

modules. In contrast, other researchers developed a low-cost

BOSA module by adopting a coaxial transistor outline

(TO)-Can structure and a bulk optical coupling mechanism [8]–[11].

These TO-Can-packaged BOSA modules have been installed

extensively in the present FTTH systems. However, the

trans-mission rate of those BOSA modules was limited to 1.25 Gb/s

[1]–[11]. This is due to some fabrication bottlenecks, such as

the lack of related components, a tighter alignment tolerance

at the receiver (Rx) end, and the difficulty of handling 10-Gb/s

signals. Due to the growing bandwidth demand, improving the

transmission rate to 10 Gb/s is crucial to the future of the

network for low-cost and wide-bandwidth FTTH applications.

The purpose of this paper is to develop both

high-performance and low-cost 10-Gb/s BOSA modules for FTTH

applications. The transmitter (Tx) side of the BOSA

mod-ule adopted an uncooled 1.3-µm 10-Gb/s TO-56-packaged

distributed-feedback (DFB) laser diode to emit the optical

signal. A matching resistor was inserted to reduce the resonant

phenomenon and to decrease the signal reflection. The Rx side

of the BOSA module consisted of a 10-Gb/s TO-46-packaged

p-i-n/transimpedance amplifier (TIA) to detect a 1.55-µm

op-tical signal. This p-i-n/TIA was packaged with a low

para-sitic inductance design, which enabled 10-Gb/s operation. A

45

tilted wavelength-division multiplexing (WDM) filter was

constructed to split the 1.3- and 1.55-µm optical signals. For

cost consideration, the optical coupling structure of the BOSA

module adapted the idea of commercial low-bit-rate (155 Mb/s

or 1.25 Gb/s) BOSA modules. Most of the optical components

inside the module and assembling processes are compatible

with the existing coaxial TO-Can approaches. The Tx and

Rx performances of the BOSA module were characterized

completely and could meet with the requirement of the OC-192

standard. Adopting this high-performance and low-cost BOSA

module will reduce the installation cost and will significantly

improve the bandwidth of a next-generation access network.

The other sections of this paper are organized as

fol-lows: Section II describes the device structure and fabrication

process. The measurement results of the BOSA modules for the

Tx and Rx characteristics are presented in Section III. A brief

conclusion is given in Section IV.

SHIH et al.: HIGH-PERFORMANCE AND LOW-COST 10-Gb/s BOSA MODULES 3493

the feasibility of 10-Gb/s transmissions at the bidirectional

architecture for use in next-generation high-bandwidth FTTH

or passive optical network applications. The proposed 10-Gb/s

BOSA modules adopted commercialized TO-Can materials,

which were about five to ten times less costly than butterfly

or dual inline package materials; therefore, the fabrication cost

of the proposed BOSA could be significantly reduced. To the

best of knowledge of the authors, such a high-performance

and low-cost 10-Gb/s BOSA module that is achieved by using

standard TO-Can materials and processes has hitherto not been

reported.

A

The authors would like to thank T.-S. Horng, National Sun

Yat-Sen University, for technical support.

R

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Tien-Tsorng Shih was born in Taiwan, R.O.C.,

in 1965. He received the B.S. and Ph.D. degrees from the National Chiao Tung University, Hsinchu, Taiwan, in 1986 and 1991, respectively.

In 1991, he joined Chunghwa Telecommunication Laboratories (formerly Telecommunication Labora-tories), Taoyuan, Taiwan, as a Research Associate and was a Project Manager from 1996 to 2000. In 2000, he founded Infomax Optical Technology Cor-poration and was the CEO during 2000–2003. He is currently an Assistant Professor with the Department of Electronics Engineering, National Kaohsiung University of Applied Sci-ences, 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 communication applications.

Min-Ching Lin received the B.S. degree in

electri-cal engineering from Yuan-Ze University, Taoyuan, Taiwan, R.O.C., in 2001 and the M.S. degree from the National Sun Yat-Sen University, Kaohsiung, Taiwan, in 2003. He is currently working toward the Ph.D. degree with the Institute of Electro-Optical Engineering, National Sun Yat-Sen University.

His main research interests include high-speed optoelectronic packaging and radio-frequency circuit design for telecommunication applications.

Pei-Hao Tseng received the B.S. degree in electrical

engineering from Chung Hua University, Hsinchu, Taiwan, R.O.C., in 2004 and the M.S. degree in photonics and communications engineering from the National Kaohsiung University of Applied Sciences, Kaohsiung, Taiwan, in 2007. He is currently working toward the Ph.D. degree with the Institute of Electro-Optical Engineering, National Sun Yat-Sen Univer-sity, Kaohsiung.

His research interests include radio-frequency cir-cuit design and measurement for telecommunication applications.

Chang-You Li, photograph and biography not available at the time of

publication.

Tuan-Yu Hung, photograph and biography not available at the time of

3494 JOURNAL OF LIGHTWAVE TECHNOLOGY, VOL. 25, NO. 11, NOVEMBER 2007

Yi-Jen Chiu (S’98–M’99) received the B.S. degree

from the National Cheng-Kung University, Tainan, Taiwan, R.O.C., in 1989, the M.S. degree from the National Taiwan University, Taipei, Taiwan, in 1991, and the Ph.D. degree from the University of California, Santa Barbara, in 1999.

After receiving his Ph.D. degree, he continued his research with the Department of Electrical and Com-puter Engineering, University of California, Santa Barbara. In 2002, he joined the faculty at the Na-tional Sun Yat-Sen University, Kaohsiung, Taiwan, where he is currently an Associate Professor. His current research interests involve the material characterization, device design, and fabrication of InAl-GaAs/InP and InGaAsP/InP high-speed electroabsorption modulators, integra-tion, and the related optical fiber system measurement.

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 Oklahoma State University, Stillwater, in 1978.

From 1978 to 1980, he was a Research Asso-ciate with Chunghwa Telecommunication Labora-tories (formerly Telecommunication LaboraLabora-tories), Taoyuan, Taiwan. From 1980 to 1984, he was a Research Engineer with General Optronics, Edison, NJ. From 1984 to 1991, he was a Principal De-sign 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 and the Director of the Southern Taiwan Opto-Electronic Center of Excellence, National Sun Yat-Sen Uni-versity, Kaohsiung, Taiwan. He has served as a Consultant with Chunghwa Telecommunication Laboratories, Opto-Electronics and System Laboratories, and Chung-Shan Institute of Science and Technology, all in Taiwan. His re-search and development activities have been focused on the design and fabrica-tion of high-speed semiconductor lasers for lightwave communicafabrica-tions, highly efficient light coupling from lasers into fibers, fiber couplers, characterization of III–V semiconductor materials, and optoelectronic packaging. His current research interests include the design, fabrication, and finite-element-method analysis for laser module packaging, high-speed laser module packaging for digital lightwave systems, fabrication of high-density WDM 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 (LEOS), Taipei Chapter, during 1999–2000 and served as a Chair for the OSA, Taiwan Chapter, during 2005–2006.