Generation of 5-Gbps QPSK signal using directly modulated RSOA for 100-km coherent WDM PON

We generate the QPSK signal by utilizing the chirp characteristics of the directly modulated RSOA for the high-speed coherent WDM PON. In addition, we demonstrate the error-free transmission of the 5-Gbps QPSK signal generated by using this technique over 100-km long fiber link without using any optical amplifiers and electronic equalizers.