Low-Penalty 5 $,\times ,$ 320 Gb/s/Single-Channel WDM DPSK Transmission Over 525 km Using Time-Domain Optical Fourier Transformation

Ultrahigh-speed wavelength-division-multiplexing transmission at 5times320 Gb/s/single channel is successfully demonstrated over 525 km using time-domain optical Fourier transformation (OFT). The modulation format is optical time-division multiplexing/differential phase-shift keying. We first suppressed signal distortions by using dispersion management and principal state of polarization launch, where the power penalty was 3.3-4.2 dB. Then, by further applying OFT, the transmission performance was greatly improved, in which a power penalty as small as 1.3-2.1 dB was achieved for all channels without using forward-error correction.