Practical Spectral Efficiency Estimation for Optical Networking

Assigning the right spectral resources is the key to flex-grid optical networking. Finding the optimal spectral allocation is a daunting task, as there are many variables at play that make accurate network models very complex. From a fiber transmission perspective, several impairments, such as amplified spontaneous emission (ASE) noise from amplifiers or nonlinear interference noise (NLIN) generated through transmission, set a limit on spectral efficiency (SE). From a transceiver perspective, modulation format, signal intensity, and spectral allocation affect the achievable capacity. On top of that, the network conditions are dynamic, causing the channel capacity to change over time. Several models have been proposed to estimate SE, ranging from the simplest to more sophisticated ones. If one is willing to sacrifice a small fraction of accuracy in exchange for a very fast service setup, some bounds can be found to guarantee a static level of service. In this work, we evaluate the degree of inaccuracy introduced by the different strategies and their complexity-accuracy trade-offs.