An Experimental Demonstration of FSK-SIM-PDM Underwater Optical Wireless Communications

This paper presents an experimental performance of frequency-shift keying with subcarrier intensity modulation (FSK-SIM) implemented along with polarisation division multiplexing (PDM) for underwater optical wireless communications (UOWC). The FSK-SIM-PDM technique demonstrated in this paper is shown to provide a resilience to the effects of turbulence whilst doubling the spectral efficiency compared to FSK-SIM. The performance of FSK-SIM-PDM is evaluated in terms of the power spectral density (PSD) and error performance of the received signals in still and turbulent water conditions. The results show that a data rate of 1.9 Gbps in still water and 1.75 Gbps in turbulent water can be achieved with FSK-SIMPDM.