Abstract
We quantify the benefits of intra-channel nonlinear compensation in meshed optical networks, in view of network configuration, fibre design aspect, and dispersion management. We report that for a WDM optical transport network employing flexible 28Gbaud PM-mQAM transponders with no in-line dispersion compensation, intra-channel nonlinear compensation, for PM-16QAM through traffic, offers significant improvements of up to 4dB in nonlinear tolerance (Q-factor) irrespective of the co-propagating modulation format, and that this benefit is further enhanced (1.5dB) by increasing local link dispersion. For dispersion managed links, we further report that advantages of intra-channel nonlinear compensation increase with in-line dispersion compensation ratio, with 1.5dB improvements after 95% in-line dispersion compensation, compared to uncompensated transmission.
Highlights
Higher-order modulation formats are used to improve spectral efficiency, but generally their tolerance towards channel impairments decreases [1,2]
We quantify the benefits of intra-channel nonlinear compensation in meshed optical networks, in view of network configuration, fibre design aspect, and dispersion management
We report that for a wavelength division multiplexed (WDM) optical transport network employing flexible 28Gbaud PMmQAM transponders with no in-line dispersion compensation, intrachannel nonlinear compensation, for PM-16QAM through traffic, offers significant improvements of up to 4dB in nonlinear tolerance (Q-factor) irrespective of the co-propagating modulation format, and that this benefit is further enhanced (1.5dB) by increasing local link dispersion
Summary
Higher-order modulation formats are used to improve spectral efficiency, but generally their tolerance towards channel impairments decreases [1,2]. With the advent of coherent systems, digital signal processing (DSP) has enabled electronic domain impairment compensation removing the need for low residual dispersion [5], electronic filtering allowing for significantly reduced guard bands between channels, and improved OSNR tolerance. All of these aspects have altered the nonlinear dynamics of the link. A vital aspect, from system design viewpoint, is to determine the benefits available with DSP in already existing maps, and if dispersion management has any role to play in future network deployments Another approach to improve nonlinear tolerance is the use of fibres with higher local dispersion coefficients. Our results are consistent with earlier results which show that with strong dispersion management, dispersion pre-compensation enables improved performance; greater improvements are enabled by intra-channel nonlinear compensation for strongly dispersion managed links, compared to uncompensated maps
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