On the next generation bandwidth variable transponders for future flexible optical systems

Elastic optical networks represent one of the most promising candidates for the imminent upgrade of current fixed-grid based optical systems. This novel architecture based on high efficient spectrum allocation (i.e. higher capacity), is necessary to cope with foreseen future exponential increase of Internet traffic. This work discusses the influence of hardware components on the transmission performance of recently proposed bandwidth variable transponders employing digital signal processing algorithms. Both are key elements for the realization of future elastic optical networks, and only their successful interplay with coherent detection can enable the transmission of different modulation formats at variable symbol and data-rates over flexible links. We evaluate the performance of such transponders when different modulation schemes are generated employing ideal and realistic values for some key hardware components. Finally, we briefly present a couple of examples of mitigation techniques: namely digital pre-distortion and digital back-propagation.