Nonlinearity limitations when mixing 40-Gb/s coherent PDM-QPSK channels with preexisting 10-Gb/s NRZ channels
01 July 2008
We investigate the penalties onto a 40-Gb/s polarization-division-multiplexing (PDM)-quadrature phase-shift keying caused by PDM, wavelength-division multiplexing and 10-Gb/s nonreturn-to-zero neighbor channels. Besides, we optimize the carrier phase estimation process and introduce bandgaps in the multiplex in order to contain limitations caused by cross nonlinear effects.