Performance Evaluation of Underwater Wireless Optical Communication System by Varying the Environmental Parameters  
[PERSON]  
1 Department of Electronics and Computer Engineering, National Taiwan University of Science and Technology, Taipei 106335, Taiwan; [EMAIL_ADDRESS] (D.-C.L. ); [EMAIL_ADDRESS] (C.-C.C. ); [EMAIL_ADDRESS] (J.-Y.S.) [PERSON]  
1 Department of Electronics and Computer Engineering, National Taiwan University of Science and Technology, Taipei 106335, Taiwan; [EMAIL_ADDRESS] (D.-C.L. ); [EMAIL_ADDRESS] (C.-C.C. ); [EMAIL_ADDRESS] (J.-Y.S.) [PERSON]  
1 Department of Electronics and Computer Engineering, National Taiwan University of Science and Technology, Taipei 106335, Taiwan; [EMAIL_ADDRESS] (D.-C.L. ); [EMAIL_ADDRESS] (C.-C.C. ); [EMAIL_ADDRESS] (J.-Y.S.) [PERSON]  
1 Department of Electronics and Computer Engineering, National Taiwan University of Science and Technology, Taipei 106335, Taiwan; [EMAIL_ADDRESS] (D.-C.L. ); [EMAIL_ADDRESS] (C.-C.C. ); [EMAIL_ADDRESS] (J.-Y.S.) [PERSON]  
1 Department of Electronics and Computer Engineering, National Taiwan University of Science and Technology, Taipei 106335, Taiwan; d10604801@gaps. studied jamming-mitigation and performance evaluation of FSO in [4], [PERSON] et al. demonstrated FSO-based fronthaul networks in [5], [PERSON] et al. proposed an FSO access network that allows 25 km fiber transmission under different weather conditions in [6]. Moreover, [PERSON] et al. investigate FSO links over strong turbulence combined with various pointing error conditions in [7]. On the contrary, underwater wireless optical communication is seldom studied because it is more difficult to set up, and the light source is limited in visible light. Due to the abundant marine resources, many scholars have studied the underwater wireless optical communication system. UWOC is more challenging than other wireless optical communication systems. It can be used for real-time video transmission in oceanographic research, offshore oil exploration, seabed measurement, monitoring, etc. [PERSON] et al. reviewed recent progress in and perspectives of UWOC [8]. [PERSON] found that the attenuation of blue and green light in water is much smaller than that of red light in the wavelength range of 450-550 nm [9]. [PERSON] proved that the attenuation of blue-green light in water is relatively small, which laid the foundation for the UWOC system [10]. These applications in the underwater medium environment are required to communicate with the outside world. [PERSON] et al. demonstrated a high-speed UWOC link using TO-9 pigtailed 520 nm LD with data rates up to 23 Gbit/s over a 7 m distance using the OOK-NRZ modulation scheme [11]. [PERSON] et al. demonstrated a high-speed UWOC link using 450 nm laser diode and an avalanche photodetector offering a data rate up to 2 Gbps over a 12-m long and 1.5 Gbps over a record 20-m long underwater channel [12]. [PERSON] et al. proposed a UWOC system using InGaN-based laser 450 nm wavelength with 4.7 Gbit/s data rate NRZ-OOK signal under different water-types [13]. [PERSON] et al. achieved 5.3 Gbps transmission without power-loading (PL) transmission and 5.5 Gbps PL transmission in 5 m air channel and 21 m underwater channel [14]. [PERSON] constructed an underwater OWC system in a 1.6 m water tank using blue and green laser sources for bidirectional transmission and successfully transmitted at a 100 Mbps transmission rate [15]. [PERSON] et al. proposed a wavelength division multiplexing (WDM), four-level pulse amplitude modulation (PAM4) methodology with a channel capacity of 100 Gb/s. They set up a 500 m free-space and 5 m UWOC system [16]. To sum up, most of the research works above focused on improving the distance and transmission speed of UWOC. The signal performance degradation affected by practical environmental factors such as flow turbulence and temperature variation has seldom been studied either by experiments or theory.