Channel model for the dual-polarization b-modulated nonlinear frequency-division multiplexing optical transmission...

Area of Science:

• Optical Communications Engineering
• Nonlinear Optics
• Signal Processing

Background:

• Nonlinear Frequency Division Multiplexing (NFDM) utilizes the nonlinear Fourier transform (NFT) for advanced optical signal processing and data modulation.
• Double-Polarization (DP) NFDM systems, particularly those employing b-modulation, offer high efficiency but require accurate modeling of noise characteristics.
• Existing analytical approaches based on adiabatic perturbation theory need extension to handle the complexities of DP-NFDM systems.

Purpose of the Study:

• To extend the adiabatic perturbation theory for continuous nonlinear Fourier spectrum (b-coefficient) to the double-polarization (DP) NFDM case.
• To derive an asymptotic channel model describing the input-output signal relation in arbitrary b-modulated DP-NFDM optical systems.
• To obtain analytical expressions for the power spectral density of input-dependent noise within the nonlinear Fourier domain.

Main Methods:

• Extension of the adiabatic perturbation theory to a double-polarization nonlinear Fourier transform (NFT) framework.
• Derivation of the leading-order continuous input-output signal relation, forming an asymptotic channel model.
• Analytical calculation of the power spectral density for effective conditionally Gaussian input-dependent noise components.

Main Results:

• Development of relatively simple analytical expressions for the power spectral density of noise in the nonlinear Fourier domain for DP-NFDM systems.
• Demonstration of remarkable agreement between derived analytical expressions and numerical simulation results.
• Identification and characterization of 'processing noise' arising from numerical inaccuracies in NFT operations.

Conclusions:

• The study provides a validated analytical model for noise in DP-NFDM optical communication systems, crucial for system design and performance prediction.
• The derived expressions facilitate a deeper understanding of noise mechanisms in advanced optical transmission systems employing b-modulation.
• The findings support the practical implementation and optimization of high-capacity optical networks leveraging NFDM technology.