期刊名称：International Journal of Innovative Research in Computer and Communication Engineering
印刷版ISSN：2320-9798
电子版ISSN：2320-9801
出版年度：2015
卷号：3
期号：8
DOI：10.15680/IJIRCCE.2015. 0308009
出版社：S&S Publications
摘要：This paper presents the comparison of QAM, DPSK and PSK modulation techniques for coherentoptical communication system to achieve better performance. It is found that the signal can be transmitted with QAMmodulation technique over a long distance without any degradation in the Q factor and BER. The acceptable value isachieved in terms of Q factor and BER at 60km distance with a bit rate of 10Gbps for different modulation techniques.By increasing the length of fiber, the signal points going to be closer in the constellation diagram. The power of QAMis constant, whereas the DPSK and PSK it exhibits fluctuations with time. The spectrum width of QAM is narrowerthan other techniques. QAM also provide highest Q factor of 12.11 and lowest BER of 4.66e-034 at 60km distance.
