Status and Recent Advances on Forward Error Correction Technologies for Lightwave Systems

Since the introduction of coherent transponders, forward error correction based on soft decision is now established in optical communication. In this paper, we give a tutorial-style introduction of one class of commonly used codes, namely low-density parity-check (LDPC) codes. Also we discuss new developments such as convolutional LDPC codes and show how they can be employed as potential candidates for future optical communication systems.