The goal of long haul DWDM transmission is to deliver error-free digital information at extremely high data rates and over very long distances, ideally without the need for regeneration of the signal. Forward error correction (FEC) is a method of encoding a signal with additional overhead information so that optical receivers can detect and correct errors that occur in the transmission path. The latest enhancement for FEC is the use of a soft decision algorithm that significantly improves the optical reach. This study evaluates the impact of soft decision forward error correction (SD-FEC) technology upon network design and economics in a long haul optical transport network. The network study shows that the SD-FEC technology not only reduces the total cost of ownership, but also simplifies the network design. Real-world network models are utilized to quantify and compare results.
