We investigate the application of time and frequency packing techniques, an extension of the classical faster-than-Nyquist signaling, to long-haul optical links. These techniques provide a significant spectral efficiency increase and represent a viable alternative to overcome the theoretical and technological issues related to the use of high-order modulation formats. Adopting these techniques, we successfully demonstrate through simulations the transmission of 1 Tbps over 200 GHz bandwidth in a realistic (nonlinear) long-haul optical link.
Faster-than-Nyquist and beyond: how to improve spectral efficiency by accepting interference / Colavolpe, Giulio; Foggi, Tommaso; Modenini, Andrea; Piemontese, Amina. - In: OPTICS EXPRESS. - ISSN 1094-4087. - 19(2011), pp. 26600-26609. [10.1364/OE.19.026600]