Real time low-complexity adaptive channel equalization for coherent optical transmission systems

In this paper, a novel low-complexity adaptive channel equalization (ACE) algorithm for digital coherent optical systems is proposed and experimentally demonstrated. We divide the conventional N-tap butterfly ACE into two N-tap polarization independent filters and a 1-tap butterfly adaptive equalization filter. The computational complexity can reduce about 40% of multiplier operations in the digital signal processing (DSP). We evaluate the effectiveness of our proposed ACE algorithm in a 10-Gb/s real-time coherent transmission platform. It is shown that our proposed ACE algorithm has similar performance as conventional ACE algorithm and better polarization tracking ability.