Abstract
As the increase of the growing demand for network transmission, it requires huge data capacity in data centers. It is necessary that establishing a communication system with lower cost and higher capacity. Optical 4-ary pulse amplitude modulation format(PAM4) is a feasible method. Relative to binary signal, PAM4 can double the data rate and offers higher spectral efficiency. However, when PAM4 in the high-speed transmission, the dispersion limits the transmission distance of signal. In the thesis, we transform the PAM4 format into Duobinary PAM4 format. This low cost and low-complexity encoding reduces the requirement of the signal by half, increasing the dispersion tolerance and transmission distance. In addition, we analyze the linearity of the optical modulator to optimize the signal-to-noise ratio(SNR) of the system. We find a most cost-effective and most efficient communication system.