BER OF ANNULAR BEAMS IN WEAK OCEANIC TURBULENCE

Based on Rytov method, on-axis scintillation index of laser communication link in a weak oceanic medium is formulated for collimated annular beam. Employing these obtained scintillation values, average bit error rate ( BER ) is evaluated where the intensity has log-normal distribution. Scintillation indices of collimated annular beams are found for fixed primary source size α_s1, varying annular beam thickness, propagation distance L , source size α_s , the rate of dissipation of the mean squared temperature XT , non-dimensional parameter representing the relative strength of temperature and salinity fluctuation w. BER versus the source size and the average signal to noise SNR found for the collimated annular beams are exhibited for various rate of dissipation of turbulent kinetic energy per unit mass of fluid Ɛ and source sizes α_s . At the stated link lengths, as secondary source size of annular beam equals to zero, that is, for Gaussian beam, BER will offer more advantages.