Transmission impairments study of 160 Gb/s generated thought a flat comb source

In this paper, we investigate an optical multicarrier source to achieve 160 Gb/s by wavelength using Polarization Multiplexing-Differential Quadrature Phase Shift Keying (POLMUX-DQPSK) and Dual Carrier-Differential Quadrature Phase Shift Keying (DC-DQPSK) with 33RZ (Return-to-Zero) pulse carving and coherent detection. The optical multicarrier source is generated by the means of a Dual-arm Mach-Zehnder Modulator (MZM) fed by a sinusoidal signal in order to generate an Optical Flat Comb Source (OFCS) spaced by the driven sinusoidal frequency. We compare the performance of the both configurations to the conventional single polarization 33RZ-DQPSK and Non-Return-to-Zero-On Off Keying (NRZ-OOK). We discuss their back-to-back receiver sensitivity and required Optical-to-Noise Signal Ratio (OSNR) for 10^-9 Bit Error Rate (BER). We find, in back-to-back configuration, that 33RZ-POLMUX-DQPSK has the best receiver sensitivity and the least penalized format in terms of OSNR. We study also the robustness of these optical modulation formats against the optical fibre impairment. We find that 33RZ-DC-DQPSK has the best behaviour.