Low complexity equalization in coherent optical communication based on Fermat number transform.

Area of Science:

• Optical Communications
• Digital Signal Processing
• High-Speed Networks

Background:

• Power consumption in digital signal processing (DSP) is a critical challenge in high-capacity coherent optical communication systems.
• Existing equalization schemes like frequency-domain equalization (FDE) and time-domain equalization (TDE) often involve high computational complexity.

Purpose of the Study:

• To propose a novel, low-complexity equalization scheme for 400 Gb/s dual-polarization 16-quadrature amplitude modulation (DP-16QAM) systems.
• To reduce the power consumption of DSP in coherent optical systems through an efficient equalization technique.

Main Methods:

• The proposed scheme utilizes Fermat Number Transform (FNT) for equalization in the transform domain.
• It sequentially performs static equalization (SE) and dynamic equalization (DE) within the FNT framework.
• The method optimizes transform length and data bit width based on transmission distance to balance complexity and performance.

Main Results:

• The transform-domain equalization (TrDE) scheme achieves significantly lower computational complexity compared to traditional FDE and TDE.
• Experimental results demonstrate a reduction of over 72% in multipliers for 80, 160, and 240 km transmission scenarios.
• Performance loss is negligible, indicating optimal efficiency.

Conclusions:

• The FNT-based TrDE scheme offers a highly efficient solution for reducing DSP power consumption in high-speed coherent optical systems.
• This approach provides substantial computational advantages, especially as transmission capacity increases.
• The method achieves a favorable trade-off between complexity reduction and performance maintenance.