3 × 40-Gbps Multiplexed Optical MSK Using Quad-Mach-Zehnder IQ Modulator

In this paper a novel method is proposed and simulated to achieve 120 Gbps minimum shift keying (MSK) system by multiplexing three 40 Gbps MSK systems. Individual MSK signal is generated using Quad Mach Zehnder IQ modulator. Three 40 Gbps MSK systems are then multiplexed by using a 3 × 1 WDM Mux to obtain 120 Gbps MSK system. The final 120 Gbps MSK signal that is generated is then transmitted through a distance of 250 km through a combinations of single mode fiber along with dispersion compensation fiber and amplifiers. At the receiver section individual MSK signal is detected separately by de-multiplexing the multiplexed MSK signal and from which the required signal is recovered through a balanced detector circuit. Error free transmission was achieved along 250 km single mode fiber. BERs are measured for both back to back and after transmission. Power penalty of around 15.5 dB, 10.5 dB and 9.5 dB are observed for the individual channels.