Browsing by Author "Gercekcioglu, H."

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Citation - WoS: 22
Citation - Scopus: 23
Annular beam scintillations in non-Kolmogorov weak turbulence
(Springer, 2012) Gercekcioglu, H.; Baykal, Y.; 7812
In a weakly turbulent atmosphere governed by the non-Kolmogorov spectrum, the on-axis scintillation index is formulated and evaluated when the incidence is an annular Gaussian type. When the power law of the non-Kolmogorov spectrum is varied, the scintillation index first increases, and reaches a peak value, then starts to decrease, and eventually approaches zero. The general trend is that when turbulence has a non-Kolmogorov spectrum with power law larger than the Kolmogorov power law, the scintillation index values become smaller. For all power laws, collimated annular Gaussian beams exhibit smaller scintillations when compared to pure Gaussian beams of the same size. Intensity fluctuations at a fixed propagation distance diminish for the non-Kolmogorov spectrum with a very large power law, irrespective of the focal length and the thickness of optical annular Gaussian sources.
Citation - Scopus: 0
Multimode Laser Beam Field Correlations for Vertical Links Operating in Oceanic Turbulence
(Institute of Electrical and Electronics Engineers Inc., 2025) Gercekcioglu, H.; Baykal, Y.; Gokce, M.C.
In underwater optical vertical link medium, based on the extended Huygens-Fresnel principle, multimode laser beam field correlation is derived and evaluated analytically in the Atlantic Ocean at high latitude and high latitude- low latitudes. With the depth of seawater, the coherence length of a spherical wave operating in the underwater turbulent medium is demonstrated for the range of 0-4000 m. By utilizing the coherence length varying with parameters such as the rate of dissipation of turbulent kinetic energy per unit mass of fluid ε, the rate of dissipation of the mean squared temperature χT and nondimensional representing the relative strength of temperature and salinity fluctuations ω, which depend on depth, the field correlation is examined in detail for single modes and multimode. Their variations are exhibited. Our results indicate clearly that as the mode increases, field correlation gets better. © 1965-2012 IEEE.
Citation - Scopus: 1
Transmittance for Dense Wavelength Division Multiplexing system in non-Kolmogorov turbulence
(2012) Ata, Y.; Baykal, Y.; Gercekcioglu, H.; 7812
Transmittance for a Dense Wavelength Division Multiplexing (DWDM) system operating in non-Kolmogorov medium is evaluated. MODTRAN (MODerate resolution atmospheric TRANsmission) is also used to include the absorption and scattering effects due to atmospheric gases, aerosols and molecules. Increase in the power law of the non-Kolmogorov spectrum is found to decrease the transmittance at all the wavelengths employed in DWDM. Being valid for all the DWDM wavelengths and for all the power law exponent values of non-Kolmogorov spectra, as the turbulence falls into stronger regimes, the transmittance levels decrease. © 2012 IEEE.