Linear Feature Pre-decoupled Bi-LSTM Nonlinearity Compensation in IM/DD PAM-n Signaling Systems

We propose a novel Bi-LSTM-based nonlinearity compensation method for IM/DD PAM-n signaling in short-reach applications, which introduces linear and nonlinear feature decoupling with the integration of dispersion pre-compensation. The method effectively compensated for distorted PAM4 waveforms caused by fiber nonlinearity, with a 0.72-dB Q<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup>-factor improvement.