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arXiv · 2412.16236

On Shaping Gain of Multidimensional Constellation in Linear and Nonlinear Optical Fiber Channel

Bin Chen·Zhiwei Liang·Yi Lei·JingXin Deng·Shen Li·Gabriele Liga
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Abstract

Utilizing the multi-dimensional (MD) space for constellation shaping has been proven to be an effective approach for achieving shaping gains. Despite there exists a variety of MD modulation formats tailored for specific optical transmission scenarios, there remains a notable absence of a dependable comparison method for efficiently and promptly re-evaluating their performance in arbitrary transmission systems. In this paper, we introduce an analytical nonlinear interference (NLI) power model-based shaping gain estimation method to enable a fast performance evaluation of various MD modulation formats in coherent dual-polarization (DP) optical transmission system. In order to extend the applicability of this method to a broader set of modulation formats, we extend the established NLI model to take the 4D joint distribution into account and thus able to analyze the complex interactions of non-iid signaling in DP systems. With the help of the NLI model, we conduct a comprehensive analysis of the state-of-the-art modulation formats and investigate their actual shaping gains in two types of optical fiber communication scenarios (multi-span and single-span). The numerical simulation shows that for arbitrary modulation formats, the NLI power and relative shaping gains in terms of signal-to-noise ratio can be more accurately estimated by capturing the statistics of MD symbols. Furthermore, the proposed method further validates the effectiveness of the reported NLI-tolerant modulation format in the literature, which reveals that the linear shaping gains and modulation-dependent NLI should be jointly considered for nonlinearity mitigation.

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Bin Chen, Zhiwei Liang, Yi Lei, JingXin Deng, Shen Li, Gabriele Liga. 2024-12-19. On Shaping Gain of Multidimensional Constellation in Linear and Nonlinear Optical Fiber Channel. https://doi.org/10.1109/jsac.2025.3543507

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