( تصميم وبناء منظومة الاتصالات لاسلكية تحت الماء قصيره المدى تحت الماء )
The importance of optical wireless communication has growing for underwater channel as it has ability of equipping high bit rates based on low power and small size requirement. Also, wireless is the reliable solution typically in the case of underwater, because of this nature of such unguided medium is very harsh and rough. In this thesis DD/IM has experimentally investigated in the form of PWM. Three wavelengths have utilized (450, 532, 650) nm to assess the feasibility of selection the suitable water channel with 50mW as incident power. S/R, BER and SER have inspected for five different water channel. These are tap water, different concentrations of Maalox ( Mg(OH)2 and Al(OH)3) and salt in order to obtain high turbidity water, Results shows that Maalox and salt content decrease the received power and interrupt the communicating link. Longest wavelength demonstrates better performance due to high turbidity water which was 35.417dB and 2.1477×10-4 for S/N and BER respectively along 2m. In contrast with 532nm wavelength has a preference in clear water channel with free error S/N of 46.808dB and BER of 4.49×10-6 over 7m. Lastly, 450nm wavelength has the best power maintained through clear water channel. The five utilized water channel has compared with Iraqi's water and found approach results between concentration of Maalox and salt with Iraqi's water depending on received power results.