Underwater optical communication for high data transfer rate

• Main Author: Lim, Wee Kiat
• Other Authors: Tse Man Siu
• Format: Final Year Project
• Language: English
• Published: 2017
• Subjects: DRNTU::Engineering::Electrical and electronic engineering::Wireless communication systems
• Online Access: http://hdl.handle.net/10356/71207
• Institution: Nanyang Technological University

This paper focuses on optical communication using visible light communications (VLC) technology that transmits information using blue 405nm wavelength laser diode over water. This technology bases on the advantages of visible light communications technology to be used in underwater wireless communication. The purpose of this project is to build blue laser diodes visible light communication transceiver to achieve two-way communications data transfer of 40Mbps between computer and the internet server. For underwater optical transmission, the absorption curve for light underwater proposes that the blue-green visible light spectrum has the best penetration strength and it shifts more towards green for coastal water. This phenomenon holds true for both the signal transmission in visible light communication and the solar spectrum which may cause noise on the ocean surface. Most signal interferences and loses occur in the 0~40m depth range, however solar irradiance is still present at the depth of 300~500m in some cases. As such solar light is hard to castoff without the loss of transmitted communications signal, hence bandpass filter is highly recommended. In this report, we will also study the current method of underwater communication and its limitations, as well as the limitations of using other data transmission methods apart from visible light communications for underwater communication. From the research, it is found that the visible light communication technology is very promising for high speed wireless networks and it may serve as underwater optical wireless data communication