Spectrum and transponder optimization in survivable translucent flexible-grid optical networks

In order to support bit-rates beyond 100 Gb/s in transport networks, flexible-grid networking was proposed as a solution to exploit the spectral efficiency of advanced modulation formats without severely impairing the transmission reach. This increase in the bit-rate highlights the critical role of survivable connectivity. Considering this, we propose a planning solution for flexible-grid translucent networks with shared restoration through an ILP model and a fast, scalable heuristic. Furthermore, we propose an algorithm to calculate the backup transponder redundancy in each node when tunable transponders are in place to restore multiple optical channels. The results show considerable spectral savings from using a shared restoration scheme instead of a dedicated one and that 18% to 30% of the backup transponders can be saved through tunable optics, depending on the tuning range used.