3 April 2019 Accumulation of nonlinear interference noise in probabilistically shaped 64-quadrature amplitude modulation systems
Linan Li, Qi Zhang, Xiangjun Xin, Yongjun Wang
Author Affiliations +
Abstract
An efficient procedure is presented for evaluating the effects of modulation format on the accumulation of nonlinear interference noise (NLIN) in probabilistically shaped 28 Gbaud 64-quadrature amplitude modulation (QAM) wavelength division multiplexed (WDM) systems. The shaped symbol sequences are generated by the rate adaptive scheme concatenating a constant composition distribution matcher and a systematic forward error correction encoder. A shaping distribution based on the Maxwell–Boltzmann and the uniform distribution with the same net bit rate is considered. The NLIN variance is emulated using the accurate enhanced modulation-dependent Gaussian noise model. Accounting for the impact of higher-order standardized moments of the modulation, the dependence of NLIN variance on probabilistic shaping is determined using the proposed procedure. In addition, an increase in NLIN variance for shaping over uniform input is demonstrated. For a dual polarization (DP) fully loaded C-band WDM optical fiber system with a channel spacing of 37.5 GHz, probabilistic shaping leads to a reduction of 0.036 in the ratio of intrachannel and interchannel contributions to nonlinear noise over uniform 64-QAM for a 1500-km distance. Finally, for nine channels with DP probabilistically shaped 64-QAM input over 1500-km transmission, distributed amplification enables a reduction of 2.54 dB in the accumulation of normalized NLIN power compared to lumped amplification.
© 2019 Society of Photo-Optical Instrumentation Engineers (SPIE) 0091-3286/2019/$25.00 © 2019 SPIE
Linan Li, Qi Zhang, Xiangjun Xin, and Yongjun Wang "Accumulation of nonlinear interference noise in probabilistically shaped 64-quadrature amplitude modulation systems," Optical Engineering 58(4), 046102 (3 April 2019). https://doi.org/10.1117/1.OE.58.4.046102
Received: 24 December 2018; Accepted: 20 February 2019; Published: 3 April 2019
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KEYWORDS
Modulation

Picosecond phenomena

Complex systems

Wavelength division multiplexing

Surface plasmons

Forward error correction

Amplitude modulation

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