Abstracts for Joseph M. Kahn

The EECS Research Summary for 2003

Coded Modulation for Fiber-optical Communication Systems with Optical Amplifiers

Roy You
(Professor Joseph M. Kahn)

In this project, we investigate the effect of using multilevel signaling with coded modulation techniques for fiber-optical communication systems with optical amplifiers. Such systems are usually dominated by the beat noise of amplified spontaneous emission. After square-root transforming the received signal, we apply the coded modulation schemes such as trellis-coded modulation and multi-level coding, which lead to significant power gain. Further improvements are made by jointly optimizing the coded modulation and the signal constellation.

Send mail to the author : (ryou@eecs.berkeley.edu)

Lattice Codes for Amplified Direct-Detection Optical Systems

Wei Mao
(Professor Joseph M. Kahn)
(DARPA) DAAH01-00-C-008

In this project, we study the theory of lattice code shaping and nonequiprobable signaling for optical systems. Previous work has established results for coherent detection systems [1] and direct-detection systems without amplifiers [2].

Our work focuses on the theory of shaping and nonequiprobable signaling for amplified direct-detection systems. In such systems, the intensity-modulated signals are corrupted by the signal-spontaneous emission beat noise, which is proportional to the signal intensity.

G. D. Forney and L. Wei, "Multidimensional Constellations--Part I: Introduction, Figures of Merit, and Generalized Cross Constellations," IEEE J. Selected Areas in Communications, Vol. 7, No. 6, August 1989.
D. Shiu and J. M. Kahn, "Shaping and Nonequiprobable Signaling for Intensity-Modulated Signals," IEEE Trans. Information Theory, Vol. 45, November 1999.

Send mail to the author : (maowei@eecs.berkeley.edu)