Optimization of Q-Values for Coherent Optical Transmission Network

Abstract

In this paper we have analyzed the Gaussian Non-linear Interference (G_NLI) spectrum considering non identical channels, non-identical links and Amplified Spontaneous Emission (ASE) noise power spectrum for Coherent Optical Transmission Network (COTN) to calculate the Optical Signal to Noise Ratio (OSNR) and Quality (Q) values. In this study, three different Baud rate values (13.875Gbaud, 27.75Gbaud, and 55.5Gbaud) are considered to compute the Q values and OSNR in the COTN. Consequently, the COTN produces 111 Gb/s, 222 Gb/s and 444 Gb/s line rates for three different Baud rate values (13.875Gbaud, 27.75Gbaud, and 55.5Gbaud) respectively in PM-16QAM modulation format. It is confirmed that the OSNR is always greater than Q values. It is also found that the differences between OSNR and Q are 0.23dB, 1.73dB, and 3.24dB for 111Gb/s, 222Gb/s and 444Gb/s line rates respectively. Here transmission of launch power per span, number of channels, number of spans and the fiber dispersion in the optical link are considered.