Performance analysis of hybrid WDM-OTDM optical multicast overlay system employing 120Â Gbps polarization and subcarrier multiplexed unicast signal with 40Â Gbps multicast signal

In this paper, we have propose and investigated the performance of hybrid WDM-OTDM optical multicast overlay system which employs 120 Gbps unicast and 40 Gbps multicast data operating over SMF+DCF and amplifier link in C-band. The polarization and subcarrier multiplexed modulation formats are used to obtain 120 Gbps unicast data and DPSK (differential phase shift keying) modulation format for 40 Gbps multicast data transmission. In multicast operation, DPSK data is superimposed on to multiplexed unicast data channels. The impact of extinction ratio, input power and transmission distance on the performance of proposed system in terms of output optical power, BER and Q-factor has been investigated for both unicast and multicast data. We have also concluded that polarization and subcarrier multiplexed modulation formats are promising option to increase per channel capacity and less vulnerable to CD and PMD. In addition, the proposed system using hybrid modulation techniques offers higher bandwidth utilization efficiency at higher per channel data rate than conventional modulation formats.