Non-linear modelling and distortion compensation in optical Fast-orthogonal frequency division multiplexing systems

Abstract

Fast-OFDM-based intensity-modulation and direct-detection (IM/DD) has been proposed for deployment of cost-efficient optical access networks, due to its implementation simplicity and high spectral efficiency. In this article, the accuracy of the generalised memory polynomial (GMP) for the non-linear modelling of optical Fast-OFDM links is studied, including memory effects and considering different model parameters. After model validation using measured data of a 10 km single mode fibre link, the GMP is used for performance investigations of a distortion compensation approach to optical Fast-OFDM, for up to 16PAM modulation formats and different number of Fast-OFDM subcarriers. This study firstly reports the performance results of optical 16PAM-Fast-OFDM systems using either 2PAM- or 4PAM-based training signals for digital post-distortion and FFT-based channel estimation, and firstly investigates the influence of the zero padding (ZP) length on the performance of optical Fast-OFDM. Excellent performance improvements are achieved using the proposed distortion compensation scheme, relative to conventional system implementation.