Performance Evaluation of Underwater Wireless Optical Communications Links in the Presence of Different Air Bubble Populations

• Published in: IEEE photonics journal 2017-04, Vol.9 (2), p.1-9
• Main Authors: Oubei, Hassan Makine, ElAfandy, Rami T., Ki-Hong Park, Tien Khee Ng, Alouini, Mohamed-Slim, Ooi, Boon S.
• Format: Article
• Language: English
• Subjects: diode lasers; Oceanic propagation; oceanic turbulence; Oceans; Optical pumping; Optical refraction; Optical scattering; optical wireless communication (OWC); Sea measurements; Sociology; Statistics; underwater wireless optical communication (UWOC); visible light communication (VLC)
• ISSN: 1943-0655; 1943-0647
• DOI: 10.1109/JPHOT.2017.2682198

We experimentally evaluate the performance of underwater wireless optical communication (UWOC) links in the presence of different air bubbles. Air bubbles of different sizes and densities are generated by using an air pipe in conjunction with a submersible water pump of variable flow rate that helps break up large bubbles into smaller bubbles. Received signal intensity measurements show that bubbles significantly degrade the performance of UWOC links. Large bubbles completely obstruct the optical beam and cause a deep fade. However, as the bubble size decreases, the level of deep fade also decreases because the optical beam is less susceptible to complete obstruction, and more light reaches the detector. We also show that beam expansion could help mitigate the performance degradation due to the deep fade caused by air bubbles scatters in the channel.