Overhead-optimization of pilot-based digital signal processing for flexible high spectral efficiency transmission

Area of Science:

• Optical Communications
• Digital Signal Processing
• High-Speed Data Transmission

Background:

• Advanced modulation formats are crucial for increasing spectral efficiency in optical networks.
• Digital signal processing (DSP) plays a vital role in managing signal impairments and optimizing performance.
• Pilot-based DSP offers a promising approach for enhancing system robustness and throughput.

Purpose of the Study:

• To present a low-complexity, fully pilot-based DSP chain for high spectral efficiency optical transmission.
• To optimize the overhead of DSP pilots to balance performance gains and throughput reduction.
• To evaluate the performance of the proposed DSP chain in long-haul transmission systems.

Main Methods:

• Simulations were conducted to assess individual pilot algorithm performance.
• A 51x24 Gbaud polarization-multiplexed 64-ary quadrature amplitude modulation (PM-64QAM) superchannel was demonstrated.
• An overhead optimization technique using the system achievable information rate was developed.

Main Results:

• A spectral efficiency of 9.3 (8.3) bits/s/Hz and superchannel throughput of 11.9 (10.6) Tb/s were achieved after 480 (960) km.
• Optimal overhead was found to be 2.4%, with weak dependence on transmission distance.
• Back-to-back optimization was deemed sufficient for all tested distances.

Conclusions:

• Pilot-based DSP combined with overhead optimization enhances robustness and performance for advanced modulation formats.
• The proposed technique maintains state-of-the-art spectral efficiency and multi-terabit per second throughput.
• This approach is suitable for future high-capacity optical transmission systems.