Mitigating Fiber Nonlinearities by Short-length Probabilistic Shaping

Fehenberger, Tobias; Grießer, Helmut; Elbers, Jörg-Peter

doi:10.1364/ofc.2020.th1i.2

Cited by 32 publications

(25 citation statements)

References 13 publications

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“…The dependence of nonlinear tolerance on shaping length was investigated using constant composition distribution matching (CCDM) [30], [31] and ESS [27], [32] for multi-span long-haul links. Also, the advantage of 2D symbol mapping for nonlinearity tolerance has been mentioned previously in [31], while the advantage of the short-length shaping regime for a nonlinear optical channel was theoretically investigated in [33], [34].…”

Section: Introductionmentioning

confidence: 99%

Huffman-Coded Sphere Shaping for Extended-Reach Single-Span Links

Skvortcov

Phillips

Forysiak

et al. 2021

IEEE J. Select. Topics Quantum Electron.

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Huffman-coded sphere shaping (HCSS) is an algorithm for finite-length probabilistic constellation shaping, which provides nearly optimal energy efficiency at low implementation complexity. In this paper, we experimentally study the nonlinear performance of HCSS employing dual-polarization 64-ary quadrature amplitude modulation (DP-64QAM) in an extendedreach single-span link comprising 200 km of standard singlemode fiber (SSMF). We investigate the effects of shaping sequence length, dimensionality of symbol mapping, and shaping rate. We determine that the naïve approach of Maxwell-Boltzmann distribution matching -which is optimal in the additive white Gaussian noise channel -provides a maximum achievable information rate (AIR) gain of 0.18 bits/4D-symbol with respect to uniform signaling at optimum launch power in the infinite length regime. Conversely, HCSS can achieve a gain of 0.37 bits/4Dsymbol over uniform signaling using amplitude sequence length of 32, which may be implemented without multiplications, using integer comparison and addition operations only. Coded system performance, with a net data rate of approximately 425 Gb/s for both shaped and uniform inputs, is also analyzed.

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Section: Introductionmentioning

confidence: 99%

Huffman-Coded Sphere Shaping for Extended-Reach Single-Span Links

Skvortcov

Phillips

Forysiak

et al. 2021

IEEE J. Select. Topics Quantum Electron.

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“…Copyright (c) 2020 IEEE nonlinearities in long-haul transmission [11] and unrepeated transmission [12]. The advantage of short-length probabilistic shaping for the nonlinear channel was thus investigated for multi-span long-haul links using constant composition distribution matching (CCDM) [13], [14] and enumerative sphere shaping (ESS) [15], [16]. Furthermore, significant shaping gain exceeding the theoretical gain for the linear channel was demonstrated for single-span links by optimally combining linear and nonlinear shaping gain contributions using shell mapping with very short shaping length [17].…”

Section: Introductionmentioning

confidence: 99%

Nonlinearity Tolerant LUT-Based Probabilistic Shaping for Extended-Reach Single-Span Links

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Phillips

Forysiak

et al. 2020

IEEE Photon. Technol. Lett.

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We propose Huffman-coded sphere shaping (HCSS) as a method for probabilistic constellation shaping which provides improved tolerance to fiber nonlinearities in single-span links. An implementation of this algorithm based on look-up-tables (LUTs) allows for low-complexity, multiplier-free shaping. The advantage of short-length shaping for mitigating fiber nonlinear impairments is experimentally demonstrated for a system employing dual-polarization 64-ary quadrature amplitude modulation (DP-64QAM) at 56 GBd and operating over 210 km of standard single-mode fiber (SSMF). A gain in achievable information rate (AIR) of 0.4 bits/4D-symbol compared with uniform signaling is measured, corresponding to a 100% improvement in shaping gain compared with ideal Maxwell-Boltzmann (MB) shaping. The combinatorial mapping and demapping algorithms can be implemented with integer addition and comparison operations only, utilizing an LUT with 100 kbit size.

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“…symbols with the MB distribution are considered as a starting point (η = 100%) for the unbiased distribution (solid lines), the performance improves by 0.11bits/symbol/pol and 0.06bits/symbol/pol, without and with DBP, respectively. Interestingly, the gain provided by sequence selection in the case without DBP is 0.05 bits/symbol/pol larger than the gain provided by PAS with optimized block length [18]- [20] . When DBP is used, the two techniques-sequence selection with MB symbols and optimized ESS without sequence selectionprovide the same gain.…”

Section: System Setup and Resultsmentioning

confidence: 87%