Digital backpropagation accounting for polarization-mode dispersion.

Area of Science:

• Optical Communications
• Digital Signal Processing
• Nonlinear Optics

Background:

• Digital backpropagation (DBP) effectively mitigates Kerr-induced nonlinear interference in optical systems.
• Ideal DBP performance is constrained by stochastic effects like polarization-mode dispersion (PMD).

Purpose of the Study:

• To modify the full-field DBP algorithm to incorporate and counteract PMD effects.
• To improve the signal-to-noise ratio (SNR) in digital optical communication systems affected by PMD.

Main Methods:

• A modified DBP algorithm was developed, including PMD compensation sections in the backward propagation path.
• PMD sections were analytically calculated at the receiver based on link PMD estimated from channel equalizers.
• Numerical simulations were performed to evaluate the modified DBP performance.

Main Results:

• The modified DBP algorithm successfully accounted for nonlinear polarization-related interactions.
• An additional signal-to-noise ratio gain of 1.1 dB was achieved for transmission over 1000 km.
• The proposed method demonstrates improved performance over ideal DBP in the presence of PMD.

Conclusions:

• The modified DBP algorithm effectively compensates for PMD, enhancing optical communication system performance.
• This approach offers a practical solution for mitigating combined nonlinear and polarization-related impairments.
• The results highlight the importance of accounting for stochastic effects in digital signal processing for optical networks.