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.

[1]
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.
[2]
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)