Performance enhancement of mapping multiplexing technique utilising dual-drive Mach–Zehnder modulator for metropolitan area networks

A methodology to control the eye opening distribution of mapping multiplexing technique (MMT) system is proposed and presented. The authors modelled and analysed a method to enhance the receiver sensitivity of MMT system by using optimised dual-drive Mach-Zehnder modulator. The proposed method offers larger eye opening for distorted Level-3 eyes. Based on the numerical calculation, the optimisation leads toward minimal eye closure. The performance of proposed system is shown to be improved by 6.1 dB in terms of receiver sensitivity compared with the conventional MMT system. Throughout the paper, the authors also discuss a numerical comparative analysis between the proposed MMT model, conventional MMT model, 33% return-to-zero on-off-keying (33%RZ-OOK), 50% RZ-OOK, 67% carrier-suppressed RZ-OOK and 4-ary amplitude shift keying in terms of positive chromatic dispersion tolerance and spectral efficiency.