Dispersion and nonlinearity compensation using electronic predistortion techniques

The development of CMOS-based digital signal processors, A/D and D/A converters operating at rates exceeding 20 GSa/s is enabling advances in the performance of electronic techniques to mitigate optical transmission impairments at bit-rates of 10 Gb/s and above. Digital processing techniques can be used to overcome signal distortion caused by fibre dispersion and nonlinearity, polarization mode dispersion, WDM crosstalk, and optical and electrical filtering. In this paper, recent advances in the use of signal predistortion using DSP are described, and results of simulations of long-haul 10 Gb/s transmission, investigating simultaneous compensation of chromatic dispersion and intra-channel nonlinearity are presented. Practical digital filter architectures are proposed to achieve nonlinear compensation