title: Nonlinear penalties in long-haul optical networks employing dynamic transponders.
abstract: We report for the first time, the impact of cross phase modulation in WDM optical transport networks employing dynamic 28 Gbaud PM-mQAM transponders (m = 4, 16, 64, 256). We demonstrate that if the order of QAM is adjusted to maximize the capacity of a given route, there may be a significant degradation in the transmission performance of existing traffic for a given dynamic network architecture. We further report that such degradations are correlated to the accumulated peak-to-average power ratio of the added traffic along a given path, and that managing this ratio through pre-distortion reduces the impact of adjusting the constellation size of neighboring channels.
authors.affiliation: Photonics Systems Group, Tyndall National Institute and Department of Electrical Engineering/Physics, University College Cork, Dyke Parade, Cork, Ireland. danish.rafique@tyndall.ie
authors.forename: Danish
authors.initials: D
authors.lastname: Rafique
authors.forename: Andrew D
authors.initials: AD
authors.lastname: Ellis