제   목  Gain saturation dynamics of quantum dot semiconductor optical amplifiers
강   사  Dr. Jungho Kim  
소   속  Technical University of Berlin, Institute for Solid-State Physics, Berlin, Germany
시   간  2007년 12월 27일 목요일 오전 11시  
장   소  서울대학교 신공학관 301동 1112호

Abstract
Quantum dot (QD) semiconductor optical amplifiers (SOAs) have drawn much attention as a cost-effect optical amplifier for 100 Gb/s Ethernet applications. Due to the three-dimensional carrier confinement in nano-sized QDs, QD SOAs have shown the theoretically predicted and experimentally demonstrated performance improvement over bulk or quantum well (QW) SOAs in terms of high saturation output power, ultrawide gain bandwidth, and distortion-free amplification up to 100 Gb/s. However, a comprehensive understanding of the gain saturation mechanisms in QD SOAs is still lacking, which is essential for enhancing performances and increasing its functionality.
In this talk, we numerically and experimentally investigate how high-speed gain saturation dynamics of QD SOAs is affected by injection current density and signal power. We set up multiple coupled rate equations to describe realistic carrier dynamics and optical processes among an inhomogeneously broadened QD ensemble. Small-signal cross-gain modulation responses are calculated from low to high injection current densities and compared with experimental results.

강사이력
Jungho Kim received the B.S. and M.S. degrees in electrical engineering from Seoul National University, Seoul, Korea, in 1998 and 2000, respectively, and the Ph.D. degree in electrical and computer engineering from University of Illinois at Urbana-Champaign, Urbana, IL, in 2006. During his Ph.D. course, he studied on the numerical modeling and experimental characterization of quantum-cascade and quantum-dot lasers.
From 2000 and 2001, he was a full-time researcher at the Electrical Engineering and Science Research Institute, Seoul, Korea, where he was engaged in the development of bidirectional optical transmission systems based on fiber Bragg gratings. He is currently a Postdoctoral Research Fellow in Prof. Bimberg’s group at the Institute for Solid-State Physics, Technical University of Berlin, Germany, where he is working on the development of quantum-dot semiconductor optical amplifiers. His research interest in optoelectronic devices also covers GaN-based and organic material systems.
Dr. Kim received a distinguished M.S. thesis award from the School of Electrical Engineering at Seoul National University (2000), a silver prize in the 6th Human Tech Thesis Contest sponsored by Samsung Electronics (2000), a Humboldt Research Fellowship from the Alexander von Humboldt Foundation (2006), and a Marie Curie Fellowship from the European Union (2007).