Abstract: While semiconductor lasers are one
cornerstone of the information age, their dynamical behavior is notoriously
sensitive to feedback. For example, it is known that optical feedback
from a distant partial mirror (with reflectivity as low as a part in a
million!) can send the laser into a complex dynamical state. In this state,
the laser produces a train of erratic picosecond pulses, and shuts of entirely
for tens of nanoseconds at erratic intervals ranging from an average of
100 ns up to 1 ms. Such instabilities can degrade the performance of devices
that require stable laser behavior, and they are interesting from a fundamental
nonlinear dynamics perspective. I will review our progress on suppressing
delay-induced instabilities in semiconductor lasers using chaos control
methods. In addition, I will discuss our recent program on developing high-speed
chaotic systems, based on delay-induced instabilities in semiconductor
laser, for chaos communication applications.
Biography: Daniel J. Gauthier received the B.S., M.S., and Ph.D. degrees from The Institute of Optics at the University of Rochester in 1982, 1983, and 1989, respectively. His Ph.D. research on "Instabilities and chaos of laser beams propagating through nonlinear optical media" was supervised by Prof. R.W. Boyd and partially supported through a University Research Initiative Fellowship. From 1989-1991, he developed the first continuous-wave two-photon optical laser as a post-doctoral research associate under the mentorship of Prof. T.W. Mossberg at the University of Oregon. In 1991, he joined the faculty of Duke University as an Assistant Professor of Physics and was named a Young Investigator of the U.S. Army Research Office in 1992 and the National Science Foundation in 1993. He is currently an Associate Professor of Physics and Assistant Research Professor of Biomedical Engineering at Duke, and Associate Director for the Duke Center for Nonlinear and Complex Systems. His research interests include: controlling and synchronizing the dynamics of complex electronic, optical, and biological systems; development and characterization of two-photon lasers; and applications of electromagnetically induced transparency in strongly driven atomic systems.
Refreshments will be served in the Phillips Hall Lounge at 4:15 p.m.