Lumped Compensation of Nonlinearities based on Optical Phase Conjugation

Compensation of Kerr nonlinearity-induced distortions has been shown to allow for increasing transmission rate and reach, with optical compensation techniques particularly attractive for broadband wavelength-division multiplexed (WDM) scenarios. However, they normally require additional devices within the link, which is particularly challenging for already deployed systems, and even more so for unrepeatered transmission. In this work, we focus on providing lumped optical nonlinearity suppression, either at the transmitter or at the receiver side, based on optical phase conjugation (OPC). The theory to design scaled-down OPC compensation modules is derived, and it allows to move beyond the standard mid-link OPC approach and to explore compensation modules with fibers types not directly linked to the dispersion properties of the transmission link. This design method is then validated both through numerical investigations and experimental demonstrations for a number of systems with a varying degree of complexity. Ultimately, significant performance improvement is shown by employing short OPC-based compensation structures which are carefully designed to match much longer transmission links.