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Electrical and Computer Engineering Seminar: Design of a 12.9-BS/S InP HBT Limiting Amplifier Used in Optical Transmitters
Friday, October 6, 2006 - 2:00pm to Friday, October 6, 2006 - 3:50pm

The Department of Electrical and Computer Engineering (ECE) at PSU's Maseeh College of Engineering and Computer Science presents as part of the ECE507 Seminar fall 2006 Series: Design of a 12.9-GB/S InP HBT Limiting Amplifier Used in Optical Transmitters.

Title: "Design of a 12.9-GB/S InP HBT Limiting Amplifier Used in Optical Transmitters"

Speaker: David H. Chiang, Ph.D., Senior Staff Design Engineer, Cypress Semiconductor Corporation, Beaverton, OR

Date: Friday, October 6, 2006

Time: 2:00 - 3:50 p.m.

Location: Cramer Hall, Room 71 (NOTE: This is a room change from the earlier posting)

This series is free and open to the public. For further information, contact the Department of Electrical and Computer Engineering, (503) 725-3806 or

For more information on upcoming seminars, please visit the Department Web site:


A 12.8-Gb/s InP HBT limiting amplifier used in optical transmitters for driving a distributed modulator driver has been designed and fabricated. The limiting amplifier has cross-point and gain-control features. The key block of the amplifier is a cascode emitter-coupled pair with Schottky diode output clamps to achieve the limiting function. The cross-point future is realized by generating a DC offset current for the emitter-coupled pair. The limiting amplifier was fabricated in a 1.5-m InP HBT process. The measured cross point control range is 33 to 83% and the output swing adjustment range is from 1100 to 1500 mV with input voltage swing from 1100 to 11000 mV. The experimental results of output rise and fall times are 15.8ps and 10.4ps, respectively. The measured input and output return losses at frequencies less than 20 GHz are -11 and -16.0 dB, respectively. The limiting amplifier can be integrated with a distributed modulator driver to drive a Mach-Zehnder dual-drive modulator.

Speaker Biography

David H. Chiang received his B.S. degree in physics from Tamkang University, Tamsui, Taiwan, in 1987. He received an M.S. degree from State University of New York at Buffalo, Buffalo, New York, in 1991 and a Ph.D. degree from Portland State University, Portland, Oregon, in 1998, both in electrical and computer engineering.

From 1991 to 1993, he worked for Macronix International Corporation, LTD., Hsinchu, Taiwan, where he worked on the CMOS true-and-high color RAMDAC design. From 1998 to 2001, he was with Texas Instruments, California, as a senior design engineer to work on the design of CMOS hard-disc drive read channel circuits and a 3.2-Gb/s Si-Ge laser diode driver. He was a senior staff engineer at Velocium Products, a business unit of Northrop Grumman Space Technology, California, where he designed InP HBT 10-Gb/s laser modulator and InP HBT 12.8- Gb/s limiting amplifier used in a fiber optical channel from 2001 to 2003. From August 2004 to July 2006, he was a visiting assistant professor in the Department of Electrical Engineering & Computer Science at Texas A&M University-Kingsville, Kingsville, Texas. His research interest at Texas A&M University-Kingsville was in the design of mixed-signal ICs used in communication systems.