160-Gb/s four WDM quasi-linear transmission over 225-km NZ-DSF with 75-km spacing

A 160-Gb/s four wavelength-division-multiplexing quasi-linear signal transmission was demonstrated over a 225-km nonzero dispersion-shifted fiber with 75-km spacing by using alternating polarization optical time-division multiplexing. A Q factor of about 15.0 dB was obtained after transmission on average. It was experimentally verified that exact adjustment of the dispersion compensation fiber is required with a few picosecond/nanometer steps on each channel after transmission.