2D Constellation Distortion for Subduing Equalization Noise in Bandwidth- Limited IMDD Systems

Bandwidth-limited IMDD systems suffer from the noise boosted by strong equalization at receiver. This letter proposes a multiplication-free approach that reduces impacts of equalizer-enhanced colored through time-interleaving received symbols and distorting two-dimensional (2D) constellation such correlation is subdued. The 2D distortion map predefined retrieved look-up table. proposed evaluated after linear feed-forward equalizer Volterra nonlinear equalizer. Experimental results show BER reduction 40% when employed for 135 Gbaud PAM4 110 PAM6 signals. Owing to approach, we transmit net data rate 250 Gbps/ $\lambda $ in O-band over 2 km SSMF notation="LaTeX">$3.8\times 10^{-3}$ below 6.7% overhead HD-FEC using 47 GHz SiP modulator, equalization, distortion.