The Gaussian Noise Model in the Presence of Inter-Channel Stimulated Raman Scattering

Sillekens

et al. 2019

J. Lightwave Technol.

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A closed-form formula is derived, which corrects for the modulation format dependence of the Gaussian Noise (GN) model in the presence of inter-channel stimulated Raman scattering (ISRS). The analytical result enables a rapid estimate of the nonlinear interference (NLI) for arbitrary modulation formats and avoids the need for complex integral evaluations and split-step simulations. It is shown that the modulation format dependent NLI can be approximated by two contributions, one originating from a single span and one asymptotic contribution for a large number of spans. The asymptotic contribution is solved in closed-form for an arbitrary link function, making the result applicable for generic fiber systems using lumped, distributed or hybrid amplification schemes. The methodology is applied to the ISRS GN model and a modulation format correction formula in closed-form is derived which accounts for an arbitrary number of spans, inter-channel stimulated Raman scattering, arbitrary launch power distributions and wavelength dependent dispersion and attenuation. The proposed formula is validated by numerical simulations over the entire C+L band for multiple fiber types.

“…Markers represent simulation results, while lines represent modelling results. In the case of Gaussian modulation, the ISRS GN model in integral form [34,Eq. (9)] [36, Eq.…”

Section: B Resultsmentioning

confidence: 99%

Section: B Link Function Of the Isrs Gn Modelmentioning

confidence: 99%

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A Modulation Format Correction Formula for the Gaussian Noise Model in the Presence of Inter-Channel Stimulated Raman Scattering

Sillekens

et al. 2019

J. Lightwave Technol.

Self Cite

“…However, for bandwidths beyond C-band, where ISRS cannot be neglected, the NLI coefficient itself becomes a function of the total launch power P tot and its absolute launch power distribution G Tx (f ). Similar to [25,Eq. (9)], the NLI coefficient in the presence of ISRS is given by…”

Section: A the Isrs Gn Modelmentioning

confidence: 90%

A Closed-Form Approximation of the Gaussian Noise Model in the Presence of Inter-Channel Stimulated Raman Scattering

Bayvel

2019

J. Lightwave Technol.

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150

138

An accurate, closed-form expression evaluating the nonlinear interference (NLI) power in coherent optical transmission systems in the presence of inter-channel stimulated Raman scattering (ISRS) is derived. The analytical result enables a rapid estimate of the signal-to-noise ratio (SNR) and avoids the need for integral evaluations and split-step simulations. The formula also provides new insight into the underlying parameter dependence of ISRS on the NLI. The proposed result is applicable for dispersion unmanaged, ultra-wideband transmission systems that use optical bandwidths of up to 15 THz.The accuracy of the closed-form expression is compared to numerical integration of the ISRS Gaussian Noise model and split-step simulations in a point-to-point transmission, as well as in a mesh optical network scenario.

“…This dramatically simplifies the description of ISRS which can then be parametrised by only a single parameter C r , which is a linear regression of the Raman gain spectrum. The NLI coefficient can then be written as [7], [8]…”

Section: The Isrs Gn Model In Integral-formmentioning

confidence: 99%

Overview and Comparison of Nonlinear Interference Modelling Approaches in Ultra-Wideband Optical Transmission Systems

2019 21st International Conference on Transparent Optical Networks (ICTON)

Bayvel

2019

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The recent advances in modelling nonlinear interference of systems operating beyond the C-band are discussed. Estimation accuracy as well as computational complexity of current approaches are compared and addressed. Keywords: optical fibre communication, ultra-wideband transmission, nonlinear interference, inter-channel stimulated Raman scattering INTRODUCTIONLightwave transmission extending beyond the C-band, exploiting the entire bandwidth of installed fibres, is increasingly being considered as a cost-effective alternative to deploying new multi-core/-mode fibres. However, for such ultra-wide bandwidths, the non-instantaneous nature of the nonlinear fibre response becomes significant, giving rise to inter-channel stimulated Raman scattering (ISRS). ISRS effectively transfers power from high to lower frequencies within the same optical signal. Although the physics of the interaction between the Kerr effect and ISRS are well understood [1], [2], efficient low-complexity performance models for modern coherent systems were (until recently) not available. Such models are key for efficient link design, real-time optimisation and physical layer-aware networking. Recently, much attention has been drawn to the development of such models, particularly by extending the modulation format independent Gaussian noise (GN) model to account for ISRS [3]- [11]. Extensions of the closed-form formalism for arbitrary, non-Gaussian modulation formats have been reported in [12]. Experimental demonstrations on the interaction between Kerr effect and ISRS followed up, in order to validate the theoretical predictions [5], [6], [13], [14]. To date, a number of modelling approaches exist in integral as well as in closed-form, varying in accuracy and complexity.In this paper, an overview of the recently proposed approaches of modelling nonlinear interference in ultrawideband transmission is presented. The estimation accuracies are compared to split-step simulations and their mathematical and computational complexity are briefly discussed.