All-Digital Optical Phase-Locked Loop for satellite communications under Turbulence Effects

This study proposes a new architecture for the phase detector in an all-digital Optical-Phase-Locked Loop (OPLL) to demodulate a digitally modulated optical signal from a long-distance Free Space Optics (FSO) communications system. The performance of the proposed architecture is evaluated and compared with an OPLL using an analog phase detector. In addition, a non-negligible delay is considered in the system analyses. Finally, the impact of wind speed on communication quality through the obtained Bit Error Rate (BER) from the recovered data is studied under three different atmospheric turbulence scenarios.