Performace Evaluation of ASK and DPSK Optical Coherent Systems affected by Chromatic Dispersion and Polarization Mode Dispersion

We present theoretical estimates on performances of ASK and DPSK coherent systems employing optical fibers affected by both chromatic dispersion and polarization mode dispersion. Results of simulations in terms of error probability show that, at the same bit rate, repeaterless ASK systems are intrinsically less sensitive than DPSK systems to dispersion effects.