Optimization of DSP-based Nyquist-WDM PM-16QAM Transmitter

Generation of PM-16QAM Nyquist-WDM signals in the digital domain is analyzed, by optimizing DSP and DAC parameters at different channel spacings. We show that ArcSin operation performed in DSP for compensating MZM non-linearity gives limited OSNR advantages and increases DSP complexity, but may give up to 3 dB gain in terms of launch power.