Vinayak Dangui

Network economics of optical transport networks with soft decision forward error correction (SD-FEC) technology

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.

System Penalty in Coherent Receiver Considering Distributed PMD, PDL, and ASE

Combined effects of distributed polarization mode dispersion (PMD), polarization dependent loss (PDL), and amplified-spontaneous-emission noise are considered in analyzing the bit error rate penalty of coherent transmission systems utilizing multiple-input-multiple-output equalization and least-mean-squared adaptation. A semianalytical model is used to evaluate system penalty at 10-5 probability of occurrence. It is found that a large amount of PMD in the fiber can significantly reduce the PDL penalty. Similarly, intentionally introducing PMD in the transmitter can also reduce the PDL penalty.

Recent advancements in fiber optic transmission

Recent emergence of coherent optical modem has solved a number of difficult problems in optical transmission, resulting in 10x increase in capacity. The latest research of super-channels further increases spectral efficiency and network flexibility.

The age of optical coherent communication

Recent emergence of coherent optical modem has solved a number of difficult problems in optical transmission, resulting in 10× increase in capacity. The latest research of super-channels further increases spectral efficiency and network flexibility.