Study on Access of RZ-PAM4 Signals with Different Duty Cycles in RoF System for MFH Applications

A radio over fiber (RoF) mobile fronthaul (MFH) system is proposed and demonstrated. Three different duty cycles RZ-PAM4 downlink signals generated by adjusting the clock frequency of the sine generator. 10Gbit/s 33%, 50% and 67% RZ-PAM4 signals are transmitted over different distances single mode fiber (SMF) to verify the effectiveness of long access distances. The results demonstrate that all of duty cycles RZ-P AM4 signals with duty cycle can transmit signal well as the transmission distance is less than or equal to 20km, which provides more options for users with different needs. Meanwhile, the performances with different transmission distances comparison of three RZ-PAM4 signals are accomplished. Transmitting and receiving 67% RZ-PAM4 signal provides a good scheme for long-distance access, and the receiver sensitivity is effectively enhanced using this method.