Two-Dimensional Constellation Shaping in Fiber-Optic Communications

Abstract

Constellation shaping has been widely used in optical communication systems. We review recent advances in two-dimensional constellation shaping technologies for fiber-optic communications. The system architectures that are discussed include probabilistic shaping, geometric shaping, and hybrid probabilistic-geometric shaping solutions. The performances of the three shaping schemes are also evaluated for Gaussian-noise-limited channels.

Keywords

• constellation shaping
• probabilistic shaping
• geometric shaping
• fiber-optic communications
• quadrature amplitude modulation
• mutual information
• generalized mutual information