High Speed Nonlinear Optical Transmission: Impairments and Cancellation

The growing demand for bandwidth requires the increasing of capacity and reach of wavelength-division multiplexing (WDM) systems, and simultaneous reducing of cost per bitxkm. In this report, I will at first introduce the 40 Gbit/s transponder and 40x42.8 Gbit/s WDM long-haul transmission experimental system over standard single mode fiber using all-Raman amplification in our laboratory. By optimizing the chirp of electro-absorption modulation and dispersion compensation, 42.8 Gbit/s NRZ transmission over 1200 km standard single mode fiber was achieved. Then our work about the fiber impairments in Nx40 Gbit/s WDM and polarization-division multiplexing (PDM) system will be reviewed. Also the technique to mitigate the impairment will be described. In particular, Electronic equalization used to overcome the distortion caused by inter-symbol interference (ISI) will be reviewed, and its capability of equalization for intra-channel nonlinearity will be discussed.