Sparse Volterra Equalizer to Mitigate the Nonlinear Distortion in High Power Budget IM-DD OFDM PON

Abstract

Abstract To improve the power budget for intensity-modulation direct-detection (IM-DD) orthogonal frequency division multiplexing passive optical network (OFDM PON), a high power budget downstream scheme by using the Volterra equalizer in digital signal processing (DSP) processing is proposed in this paper. When the launch power is increased, the subcarrier-to-subcarrier beating interference (SSBI) and other nonlinear distortion are well mitigated by the Volterra equalizer. Moreover, to reduce the complexity of receiver DSP unit, the sparse Volterra equalizer is obtained through optimizing full Volterra equalizer employing orthogonal search method. Simulation and experiment results are presented to evaluate the transmission performance and analyze the distribution of taps of Volterra equalizer under different respects. The results show that the number of tap coefficient of sparse Volterra equalizer is reduced by 60% compared with that of conventional second-order full Volterra equalizer.