Design of Small-area Transimpedance Optical
Receiver Module for Optical Interconnects
Jamshid Sangirov, Ikechi Augustine Ukaegbu, Nga T. H. Nguyen, Tae-Woo Lee, Mu-Hee Cho, andHyo-Hoon Park
Photonic Computer Systems Laboratory, Electrical Engineering Department, KAIST, Daejeon, Korea 305-701
jamshid@kaist.ac.kr, aus20@kaist.ac.kr, nganth@kaist.ac.kr, twlee@ee.kaist.ac.kr, chophy@kaist.ac.kr,
pakrhh@ee.kaist.ac.kr

Abstract— The development and miniaturization of complementary metal oxide semiconductor (CMOS) technology is pushing theelectronic devices and their interconnecting interfaces to become even smaller. Thus, reducing the size of receiver (Rx) and transmitter(Tx) chips plays an important role in designing a small-size optical modules utilized in o/e and e/o converters. Therefore, designing asmall-area optical Rx may require intuitive solutions, such as building single-ended Rx and utilizing some of the advantages of differentialRx. Optical Rx should convert optical input signal to voltage output signal and provide sufficient gain and frequency operation for
feeding to subsequent blocks including clock and data recovery circuit (CDR) and/or Serializer and Deserializer (SerDes). Therefore, wehave designed a small-area transimpedance optical receiver (TIORx) using regulated-cascode (RGC) as an input stage which converts
input photocurrent to voltage signal. The RGC block is connected to post amplifying stages to increase the overall transimpedance gain ofthe TIORx. The post amplifying gain stages utilizes two intersecting active feedback in order to increase the frequency operation inaddition to increasing the gain of the proposed TIORx chip. The TIORx module is designed in a 0.13μm CMOS technology and works up
to 10 Gbps data rate. The TIORx chip core occupies an area of 0.051mm2 with power consumption of 16.9 mW at 1.3 V. A measured 3-dB
bandwidth of 6.9 GHz was obtained for the TIORx module with a transimpedance gain of 60 dBΩ.
Keyword— Optical receiver, small-area circuit design, bandwidth improvement, optical interconnections

Jamshid Sangirov received the M.S. degrees in Information and Communication Engineering from Yeungnam University in 2006. Heis a Ph.D. student in Electrical Engineering at Korean Advanced Institute of Science and Technology (KAIST) since 2008, he is staying
with the Photonic Computer Systems Laboratory, KAIST. He worked with the RFIC Design Team, at Teltron Inc., Korea, from 2010 to2011. His research interests are analog/RF/VLSI and high-speed electronics, optical interconnections, optical transceiver modules.

Ikechi Augustine Ukaegbu received the B.S. degree in Electrical Engineering, Electro-mechanics, and Electro-technology, the M.S.
degree in electronics and microelectronics from Moscow Power Engineering Institute, Technical University, Moscow, Russia, in 2004
and 2006, respectively, and the Ph.D. degree in information and communications engineering from the Korea Advanced Institute ofScience and Technology (KAIST), Daejeon, Korea, in 2012. He was with the System Convergence Technology Team, Convergenceand Components Materials Research Lab, Electronics and Telecommunications Research Institute, Korea, from 2008 to 2009. He iscurrently with the Electrical Engineering Department, Photonics Computer System Laboratory, KAIST, as a Post-Doctoral Scholar.
His current research interests include optical interconnection for high speed and low loss multichannel data links in computer andcommunication systems, optical interconnections for chip-to-chip and board-to-board data links, chip design for optical transceiver modules, integration, andpackaging of optoelectronic components.

Nga T. H. Nguyen received the BS degree in Post Telecommunication Institute of Technology, Hanoi, Vietnam in 2003. She
received the M.S degree in August, 2005 and now is Ph.D candidate in Korea Advanced Institute of Science and Technology. Her
research interests are low-power and low-const optical circuit design, and building system for optical interconnection applications.

Tae-Woo Lee received the Ph.D. degree in Electronic and Electrical Engineering from the University of Sheffield, Sheffield, U.K., in1992. He was an Associate Researcher in the area of compound semiconductor devices with the University of Sheffield, from 1992 to1994. From 1994 to 2000, he was with the Electronics and Telecommunications Research Institute, Daejeon, Korea, working in the areaof high-speed electronic devices and circuits and MMIC. From 2000 to 2003, he was a CEO/CTO with the Venture Company, producing
RF PAM and MMIC modules. Since 2003, he has been a Research Professor with the Photonic Systems and Engineering Group, Korea
Advanced Institute of Science and Technology, Daejeon. His current research interests include optical interconnections for chip-to-chipand board-to-board data links, optical transceiver modules, and optical switching components for high-speed optical interconnection.

Mu Hee Cho received the Ph.D. received the Ph.D. degree in Physics from Dankook University, Cheonan, Korea, in 1999. He was with
the Zenphotonics Company, Daejeon, Korea, from 2000 to 2003, where he was engaged in the research and development ofpolymer-based optical devices. Since 2003, he has been researching on the chip-to-chip optical interconnections using optical printed
circuit boards (PCBs) as a Research Professor with the Photonic Systems and Engineering Group, Korea Advanced Institute of Scienceand Technology, Daejeon. His current research interests include high-speed optical modules, optical interconnection, and optical PCBs.

Hyo-Hoon Park received the Ph.D. degree in Material Science and Engineering from the Korea Advanced Institute of Science andTechnology (KAIST), Daejeon, Korea, in 1985. He was a Post-Doctoral Scholar in the area of compound semiconductor devices withStanford University, Stanford, CA, USA, from 1985 to 1986. From 1986 to 1997, he was with the Electronics and Telecommunications
Research Institute, Daejeon, working in the area of high-speed electronic devices and vertical-cavity surface-emitting lasers. Since 1998,
he has been a Professor with the Photonic Systems and Engineering Group, KAIST. His current research interests include opticalinterconnections for chip-to-chip and board-to-board data links, optical transceiver modules, and switching components for optical-link
computer systems.