We report the performance of coherently-detected nine-channel WDM transmission over high dispersion fibers, using polarization multiplexed m-ary quadrature amplitude modulation (m = 4, 16, 64, 256) at 112 Gbit/s. Compensation of fiber nonlinearities via digital back-propagation enables up to 10 dB improvement in maximum transmittable power and similar to 8 dB Q(eff) improvement which translates to a nine-fold enhancement in transmission reach for PM-256QAM, where the largest improvements are associated with higher-order modulation formats. We further demonstrate that even under strong nonlinear distortion the transmission reach only reduces by a factor of similar to 2.5 for a 2 unit increase in capacity (log(2)m) when full band DBP is employed, in proportion to the required back-to-back OSNR.
Bibliographical note© 2011 OSA
This paper was published in Optics Express and is made available as an electronic reprint with the permission of OSA. The paper can be found at the following URL on the OSA website: http://dx.doi.org/10.1364/OE.19.005219. Systematic or multiple reproduction or distribution to multiple locations via electronic or other means is prohibited and is subject to penalties under law.
Rafique, D., Zhao, J. A., & Ellis, A. D. (2011). Digital back-propagation for spectrally efficient WDM 112 Gbit/s PM m-ary QAM transmission. Optics Express, 19(6), 5219-5224. https://doi.org/10.1364/OE.19.005219