Effect of Link Margin on spectrum saving and advantages of flexgrid optical networking

Optical networks are now evolving due to the high bit rate demands of multimedia applications and internet services. These applications demand high bandwidth and the current fixed grid network can no longer work for data rate of 400Gbps or higher. This paper focuses on Link Margin (LM) and its effect on the spectrum saving for the demand of 100Gbps and 1000Gbps in a point to point optical link. Optical Signal to Noise Ratio (OSNR) threshold values are calculated for various Link Margins to achieve a BER of 10⁻³ for all M-ary modulation. Minimum amount of optical spectrum is allocated using the calculated OSNR threshold. Under good LM conditions, for demand of 100Gbps and 1000Gbps optical spectrum saving up to 7500Km and 1000Km is possible. Finally, we highlight the advantages of Flexgrid over Fixed grid and how it can achieve the above savings.