Open AccessExperimental Study on Transmission of Visible Light in Table Salt Water and Effect on Underwater Wireless Optical Communication
Author(s) -
Oluwabukola A. Ojediran,
Akinlolu A. Ponnle,
Samson A. Oyetunji
Publication year - 2022
Publication title -
european journal of electrical engineering and computer science
Language(s) - English
Resource type - Journals
ISSN - 2736-5751
DOI - 10.24018/ejece.2022.6.2.425
Subject(s) - molar absorptivity , attenuation coefficient , attenuation , wavelength , visible spectrum , absorption (acoustics) , seawater , underwater , materials science , optics , analytical chemistry (journal) , absorption spectroscopy , chemistry , optoelectronics , physics , environmental chemistry , oceanography , geology
Underwater wireless optical communication (UWOC) has advantages over other underwater communication methods. Some of these advantages are high data rates, large bandwidth, and less susceptibility to electromagnetic interference. The transmission of light underwater is affected by absorption, scattering and turbulence. Sodium Chloride is one of the most abundant dissolved substances in seawater which cause attenuation of optical signals. In this work, the effect of table salt in water on transmission of visible light in the range 400nm – 800nm was investigated. Nine samples of 100 ml of pure water were prepared in which eight of the samples contain addition of table salt of 1g, 3g, 4.5g, 5.5g, 15g, 20g, 25g and 28g yielding different salt concentrations (salinity). The conductivity, total dissolved solids (TDS), and total dissolved salt of the samples were measured. Absorption spectra of visible light through these samples were obtained using a spectrophotometer. The results showed an increase in conductivity and attenuation with increase in the presence of the table salt in the water. Also, it was observed that at shorter wavelengths (blue light), there is higher attenuation with increase in salt concentration compared to longer wavelengths (red light). However, the attenuation tends to increase sharply around 700nm – 800nm. From the absorption spectra obtained for each sample, the absorptivity spectrum for the table salt was obtained which shows high absorptivity at shorter wavelengths and lower absorptivity at longer wavelengths. From the absorption coefficient values obtained from the measurements, performance of UWOC for selected samples at three wavelengths of 450nm, 550nm and 700nm with transmitter power of 30mW were evaluated by simulation using OptiSystem linked with MATLAB. For a maximum allowable Bit Error Rate (BER) of 10-9 in UWOC, achievable link distance reduces considerably as the salt concentration increases.