Baykal, Yahya Kemal

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Profile URL
https://hdl.handle.net/20.500.12416/8884
Name Variants
Bayka, Yahya
Baykal, Yahya K.
Baykal, Yahya Kemal
Baykal, Yahya
Baykal, Y. K.
Baykal, Yahya Kemal
Baykal, Y
Baykal, Y.
Baykal, Yahya
Baykal, Yahya
Baykal, Yahya Kemal
Baykal, Yahya
Baykal, Yahya Kemal
Job Title
Prof. Dr.
Email Address
y.baykal@cankaya.edu.tr
Main Affiliation
06.03. Elektrik-Elektronik Mühendisliği
06. Mühendislik Fakültesi
01. Çankaya Üniversitesi
06.03. Elektrik-Elektronik Mühendisliği
Elektrik-Elektronik Mühendisliği
06. Mühendislik Fakültesi
01. Çankaya Üniversitesi
Status
Current Staff
Website
academic.cankaya.edu.tr/~y.baykal/
ORCID ID
0000-0002-4897-0474
Scopus Author ID
Turkish CoHE Profile ID
Google Scholar ID
dLX8b-oAAAAJ
WoS Researcher ID
DWS-9216-2022
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00519.jpg (76.39 KB)

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Documents

132

Citations

4320

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Scholarly Output

290

Articles

236

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3685/73

Supervised MSc Theses

10

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WoS Citation Count

6291

Scopus Citation Count

6768

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WoS Citations per Publication

21.69

Scopus Citations per Publication

23.34

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17

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10

JournalCount
Journal of the Optical Society of America A35
Optics Communications34
Applied Optics23
Applied Physics B20
Journal of Modern Optics16
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Now showing 1 - 10 of 290
  • Thumbnail Image
    Article
    Citation - WoS: 13
    Citation - Scopus: 14
    Fourth-Order Mutual Coherence Function in Oceanic Turbulence
    (Optical Soc Amer, 2016) Baykal, Yahya
    We have recently expressed the structure constant of atmospheric turbulence in terms of the oceanic turbulence parameters, which are the ratio of temperature to salinity contributions to the refractive index spectrum, rate of dissipation of kinetic energy per unit mass of fluid, rate of dissipation of the mean-squared temperature, wavelength, Kolmogorov microscale, and link length. In this paper, utilizing this recently found structure constant and the fourth-order mutual coherence function of atmospheric turbulence, we present the fourth-order mutual coherence function to be used in oceanic turbulence evaluations. Thus, the found fourth-order mutual coherence function of oceanic turbulence is evaluated for the special case of a point source located at the transmitter origin and at a single receiver point. The variations of this special case of the fourth-order mutual coherence function of oceanic turbulence against the changes in the ratio of temperature to salinity contributions to the refractive index spectrum, the rate of dissipation of kinetic energy per unit mass of fluid, the rate of dissipation of the mean-squared temperature, the wavelength, and the Kolmogorov microscale at various link lengths are presented. (C) 2016 Optical Society of America
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    Article
    Citation - WoS: 23
    Citation - Scopus: 24
    Higher-Order Laser Beam Scintillation in Weakly Turbulent Marine Atmospheric Medium
    (Optical Soc Amer, 2016) Baykal, Yahya
    The atmosphere above the sea or ocean, known as the marine atmosphere, affects optical waves propagating through it in a different manner than the atmosphere above land. Like other system design parameters, intensity fluctuations of laser light propagating in marine atmosphere, quantified by the scintillation index, also show different variations. The on-axis scintillations of higher-order laser beams are formulated and evaluated when such excitations are employed in a weakly turbulent marine atmospheric medium. Variations of the scintillation index with respect to the changes in the Gaussian beam size of the higher-order mode, link length, wavelength, and structure constant are reported. Our results can be used in the design of an optical wireless communication link design operating in marine atmospheres. (C) 2016 Optical Society of America
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    Article
    Citation - Scopus: 1
    Multimode Laser Beam Field Correlations for Vertical Links Operating in Oceanic Turbulence
    (IEEE-Inst Electrical Electronics Engineers inc, 2025) Gercekcioglu, Hamza; Baykal, Yahya; Gokce, Muhsin Caner; Caner Gokce, Muhsin
    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 epsilon, the rate of dissipation of the mean squared temperature chi(T) and non-dimensional representing the relative strength of temperature and salinity fluctuations omega, 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.
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    Article
    Citation - WoS: 24
    Citation - Scopus: 23
    Scintillation Index of Flat-Topped Gaussian Laser Beam in Strongly Turbulent Medium
    (Optical Soc Amer, 2011) Gercekcioglu, Hamza; Baykal, Yahya
    In a strongly turbulent medium, the scintillation index of flat-topped Gaussian beams is derived and evaluated. In the formulation, unified solution of Rytov method is utilized. Our results correctly reduce to the existing strong turbulence scintillation index of the Gaussian beam, and naturally to spherical and plane wave scintillations. Another checkpoint of our result is the scintillation index of flat-topped Gaussian beams in weak turbulence. Regardless of the order of flatness, scintillations of flat-topped Gaussian beams in strong turbulence are found to be determined mainly by the small-scale effects. For large-sized beams in moderate and strongly turbulent medium, flatter beams exhibit smaller scintillations. (C) 2011 Optical Society of America
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    Article
    Citation - WoS: 14
    Citation - Scopus: 15
    Intensity Correlations of General Type Beam in Weakly Turbulent Atmosphere
    (Elsevier Sci Ltd, 2011) Baykal, Yahya
    In weakly turbulent atmosphere, intensity correlations at the receiver plane are formulated for a general type optical beam. Evaluating our formula at the appropriate source parameters versus the diagonal distance, intensity correlations for cos Gaussian, cosh Gaussian, annular and flat-topped Gaussian beams are obtained. As compared to Gaussian beam, intensity correlations are found smaller for cos Gaussian and larger for cosh Gaussian beams. Intensity correlations of cos Gaussian, cosh Gaussian and flat-topped Gaussian beams become larger at large source sizes. Thicker annular beams and flatter flat-topped Gaussian beams show larger intensity correlations. Without generalizing, intensity correlations tend to increase when the link length and the structure constant decrease and the wavelength increases. Our results show that the intensity correlations are not only built up using random medium effects, but also using the diffraction pattern formed at the receiver plane for the specific incidence investigated. As a check point, for all source types and medium parameters, our evaluations indicate that intensity correlations approach zero at sufficiently large diagonal distances. (C) 2011 Elsevier Ltd. All rights reserved.
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    Article
    Citation - WoS: 21
    Citation - Scopus: 21
    Signal-To Ratio Reduction Due To Oceanic Turbulence in Oceanic Wireless Optical Communication Links
    (Elsevier Science Bv, 2018) Baykal, Yahya
    The effect of oceanic turbulence on the signal-to-noise ratio (SNR) at the receiver of an oceanic wireless optical communication (OWOC) link is studied. To quantify such effect, the metric employed is the reduction in the SNR when oceanic turbulence is present. SNR reduction due to oceanic turbulence is formulated by subtracting the 10 log (SNR) evaluated at the receiver in the presence of turbulence from the 10 log (SNR) evaluated at the receiver in the absence of turbulence. Classical SNR formula which is function of the received optical power, noise and optical detector parameters is utilized. As the average received power, our earlier result that uses a Gaussian optical source field and a finite Gaussian receiver aperture in atmospheric turbulence is adapted for oceanic turbulence and such found average received power is inserted in the SNR expression. OWOC links that use collimated Gaussian optical sources at the transmitter and PIN photodiode, avalanche photodiode (APD) at the receiver, are analyzed. Results that present the variations of the SNR reduction due to oceanic turbulence against the changes in the source, oceanic turbulence and the optical receiver parameters are reported.
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    Article
    Citation - WoS: 59
    Citation - Scopus: 62
    Scintillation of Astigmatic Dark Hollow Beams in Weak Atmospheric Turbulence
    (Optical Soc Amer, 2008) Cai, Yangjian; Eyyuboglu, Halil T.; Baykal, Yahya
    The scintillation properties of astigmatic dark hollow beams (DHBs) in weak atmospheric turbulence were investigated in detail. An explicit expression for the on-axis scintillation index of an astigmatic DH13 propagating in weak atmospheric turbulence was derived. It was found that the scintillation index value of an astigmatic DH13 with suitable astigmatism (i.e., ratio of the beam waist size in the x direction to that in the y direction), dark size, beam waist size, and wavelength can be smaller than that of a stigmatic DH13 and that of stigmatic and astigmatic flat-topped, annular, and Gaussian beams in weak atmospheric turbulence particularly at long propagation ranges. Our results will be useful in long-distance free-space optical communications. (c) 2008 Optical Society of America
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    Article
    Citation - WoS: 22
    Citation - Scopus: 20
    Scintillation Index of Optical Spherical Wave Propagating Through Biological Tissue
    (Taylor & Francis Ltd, 2017) Baykal, Yahya; Arpali, Caglar; Arpali, Serap Altay
    Effects of the tissue turbulence on the propagation of an optical spherical wave are analysed. For this purpose, scintillation index of an optical spherical wave which is propagating in a soft tissue is formulated and evaluated in weakly turbulent soft tissue. Scintillation index of the optical spherical wave is examined against the changes in the tissue parameters which are the tissue length between the optical spherical wave source and the detector, random variations in the refractive index of the tissue and the outer scale of the tissue turbulence. According to our graphical outputs, it is observed that increase in the random variations of the refractive index of the tissue results in an increase in the scintillation index at a certain realization of the turbulence spectrum. On the other hand, larger outer scales and longer tissue lengths yield larger scintillations. The variation of the scintillation index of the optical spherical wave versus the wavelength is also investigated. It is found that at small tissue lengths, wavelength has almost no effect on the scintillations; however, when the tissue length reaches a certain value, shorter wavelengths give rise to larger intensity fluctuations.
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    Conference Object
    Citation - WoS: 2
    Citation - Scopus: 3
    Method of Evaluation of the Mutual Coherence Function of Laser Beams and Its Application for Symmetric Dark Hollow Beams
    (Spie-int Soc Optical Engineering, 2011) Banakh, V. A.; Marakasov, D. A.; Rytchkov, D. S.; Baykal, Y. K.; Eyyuboglu, T.; Eyyuboǧlu, H.T.
    In our report, a method of evaluation of the mutual coherence function (MCF) of optical wave propagating in turbulent atmosphere is proposed. The method is based on using inverse Fresnel transform and 2-D Fast Fourier Transformation procedure (FFT) and provides a high accuracy in various propagation conditions from weak up to strong optical turbulence regime. This technique allows significantly reducing the evaluation time of MCF. The proposed method is suitable for optical waves with arbitrary initial distribution of amplitude and phase. Results of investigations on the degradation of coherence of symmetric dark hollow beams (DHB) propagating in turbulent atmosphere are presented. Analysis of evolution of MCF is brought up, and some characteristics of DHB, such as mean intensity distribution, and moments of Wigner distribution are calculated for various kinds of profiles of structural characteristic of refractive index. All of the evaluations for DHB are fulfilled for Kolmogorov spectrum of correlation function of refractive index fluctuations. The comparison between mean intensity calculations within the proposed method and method based on semi-analytical approach using of quadratic approximation of spherical wave structure function, is presented.
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    Article
    Citation - WoS: 40
    Citation - Scopus: 45
    Scintillation Analysis of Multiple-Input Single-Output Underwater Optical Links
    (Optical Soc Amer, 2016) Baykal, Yahya; Gokce, Muhsin Caner
    Multiple-input single-output (MISO) techniques are employed in underwater wireless optical communication (UWOC) links to mitigate the degrading effects of oceanic turbulence. In this paper, we consider a MISO UWOC system which consists of a laser beam array as transmitter and a point detector as receiver. Our aim is to find the scintillation index at the detector in order to quantify the system performance. For this purpose, the average intensity and the average of the square of the intensity are derived in underwater turbulence by using the extended Huygens-Fresnel principle. The scintillation index and the average bit-error-rate (< BER >) formulas presented in this paper depend on the oceanic turbulence parameters, such as the rate of dissipation of the mean-squared temperature, rate of dissipation of kinetic energy per unit mass of fluid, Kolmogorov microscale, and the ratio of temperature to salinity contributions to the refractive index spectrum, the link length, and the wavelength. Recently, we have derived an equivalent structure constant of atmospheric turbulence and expressed it in terms of the oceanic turbulence parameters [Appl. Opt. 55, 1228 (2016)]. In the formulation in this paper, this equivalent structure constant is utilized, which enables us to employ the existing similar formulation valid in atmospheric turbulence. (C) 2016 Optical Society of America