An Effective Combining Transformer to RelieveFiber Nonlinearity in CO-OFDM System

Abstract

This paper mainly concerns on reducing the impact of chromatic dispersion (CD) and the nonlinear(NL) impairments in coherent optical orthogonal frequency division multiplexing (CO-OFDM) system. In effect, the system suffers from a severe problem due to a high peak to average power ratio (PAPR); and this consequently degrades the system performance. In this paper, a new method is proposed to mitigate the PAPR problem and thereby reduce the impact of nonlinearity on the performance of the CO-OFDM system with quadrature amplitude modulation QAM mapping. The recommended new technique is based on combining two effective ways of clipping method integrated with the L2-by3 method. The simulation results indicate that the proposed method was effectively able to improve system performance by enhancing system performance via bit error rate (BER), quality factor (QF), error vector magnitude (EVM) beside the Optical Signal-to-Noise Ratio (OSNR) without the need to add any digital processing at the receiver; and eventually decrease the receiver complexity. The proposed method reduced the peak to average power ratio (PAPR) about 3.8 dB and helped to increase transmission distance by approximately 200 km.