More than two-thirds of the Earth’s surface is covered by water. The oceans and seas play a critical role in many of the Earth’s systems including climate, weather and food production cycles. Even though underwater communications have been under research since long time ago, most of the underwater world still remains unexplored so far. To further explore the underwater environments, developing efficient communication technology is of crucial important.Underwater wireless transmission can be achieved through radio, optical, or acoustic waves. Transmission of signal through radio water is limited to a few tens of meters. Although long distance transmission of acoustic waves has been demonstrated, transmission of signal through this technique offer a low data rate of 20 kbps.In this project,our goal is to develop a high data rate line-of-sight and non-line-of-sight underwater wireless optical communication system using highly coherent, either broad or narrow beam divergence semiconductor lasers.  When developed, this giga-bit bandwidth, kilometer range underwater communication system will enable many novel applications includes seafloor survey, underwater oil field exploration, etc. ​​​​​