IQ Skew Tolerance Study of Modified Widely Linear Filter in 400 Gbps PM-16QAM System

We study the effect of receiver IQ skew in the 448 Gbps PM-16QAM system employing a joint equalizer for polarization demultiplexing, IQ gain and phase imbalance and carrier recovery with a modified widely linear adaptive filter. Through numerical simulations, we show the performance of the joint equalizer algorithm is within the standard HD-FEC limit of 3.8 x 10−3 BER at an OSNR of 24 dB and skew tolerance upto ~ 70% of symbol duration.