Intensity fluctuations of asymmetrical optical beams in anisotropic turbulence

Baykal, Yahya

doi:10.1364/ao.55.007462

“…where κ x , κ y , and κ z are spatial frequency components in the x, y, and z directions, respectively. According to the Markov approximation, we assume that the κ z component in the anisotropic oceanic turbulent medium can be ignored due to delta correlation and spatial frequency, and κ ξ ¼ ξκ p [22] . The power spectrum of the anisotropic turbulent ocean is [10]…”

Section: Snmentioning

confidence: 99%

“…These studies [17][18][19][20] cover the log-amplitude correlation function for spherical wave propagation through anisotropic non-Kolmogorov atmosphere, average polarization of the electromagnetic Gaussian Schell model beams propagating through anisotropic non-Kolmogorov turbulence, polarization of quantization Gaussian Schell beams through anisotropic non-Kolmogorov turbulence of the marine atmosphere, and effects of anisotropic turbulence on the average polarizability of Gaussian Schell model quantized beams through an ocean link. In our earlier studies, we have reported in anisotropic oceanic turbulence, the intensity fluctuations of spherical optical beams [21] , the intensity fluctuations [22] , and the bit error rate (BER) of asymmetrical Gaussian beams [23] . In these works, the observation is that anisotropy in the turbulent ocean causes reductions in the intensity fluctuations and BER.…”

mentioning

confidence: 99%

Anisotropy effect on multi-Gaussian beam propagation in turbulent ocean

Ata

¹

,

Baykal

²

2018

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Average transmittance of multi-Gaussian (flat-topped and annular) optical beams in an anisotropic turbulent ocean is examined analytically based on the extended Huygens-Fresnel principle. Transmittance variations depending on the link length, anisotropy factor, salinity and temperature contribution factor, source size, beam flatness order of flat-topped beam, Kolmogorov microscale length, rate of dissipation of turbulent kinetic energy, rate of dissipation of the mean squared temperature, and thickness of annular beam are examined. Results show that all these parameters have effects in various forms on the average transmittance in an anisotropic turbulent ocean. Hence, the performance of optical wireless communication systems can be improved by taking into account the variation of average transmittance versus the above parameters.

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“…For optical wave propagation, the classic Kolmogorov model has been widely used in theoretical researches due to its simple mathematical form [3][4][5]. Over the years, the Kolmogorov model is extended and several non-Kolmogorov turbulence models have been also proposed [6][7][8][9][10][11][12][13]. Toselli et al [6] is one of them, and they analyze the angle of arrival fluctuations by using the generalized exponent factor α instead of the standard exponent value 11/3.…”

Section: Introductionmentioning

confidence: 99%

“…Toselli et al [6] is one of them, and they analyze the angle of arrival fluctuations by using the generalized exponent factor α instead of the standard exponent value 11/3. The anisotropic factor is also used to describe anisotropy of the atmosphere turbulence [7], and the generalized non-Kolmogorov von Karman spectrum of the anisotropic atmospheric turbulence is available [8][9][10]. In addition, there are also numerous studies on beam wanders, loss of spatial coherence, temporal frequency spread, and the angle of arrival fluctuation [14][15][16][17][18][19][20][21], which are all related to the random fluctuation of optical waves propagating through random media.…”

Section: Introductionmentioning

confidence: 99%

Spatial Property of Optical Wave Propagation through Anisotropic Atmospheric Turbulence

Guan

¹

,

Yu

²

,

Song

³

et al. 2021

Wireless Communications and Mobile Computing

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For the free-space optical (FSO) communication system, the spatial coherence of a laser beam is influenced obviously as it propagates through the atmosphere. This loss of spatial coherence limits the degree to which the laser beam is collimated or focused, resulting in a significant decrease in the power level of optical communication and radar systems. In this work, the analytic expressions of wave structure function for plane and spherical wave propagation through anisotropic non-Kolmogorov turbulence in a horizontal path are derived. Moreover, the new expressions for spatial coherence radius are obtained considering different scales of atmospheric turbulence. Using the newly obtained expressions for the spatial coherent radius, the effects of the inner scales and the outer scales of the turbulence, the power law exponent, and the anisotropic factor are analyzed. The analytical simulation results show that the wave structure functions are greatly influenced by the power law exponent α , the anisotropic factor ζ , the turbulence strength σ ~ R 2 , and the turbulence scales. Moreover, the spatial coherence radiuses are also significantly affected by the anisotropic factor ζ and the turbulence strength σ ~ R 2 , while they are gently influenced by the power law exponent α and the inner scales of the optical waves.

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“…For the optical waves propagating in terrestrial or high altitude atmospheric turbulence, the classic Kolmogorov model has been widely used in theoretical research due to its simple mathematical form [2][3][4]. Over the years, the Kolmogorov model is extended and several non-Kolmogorov turbulence models have been also proposed [5][6][7][8][9]. Toselli is one of them and he analyzes the angle of arrival fluctuations by using the generalized exponent factor α instead of the standard exponent value 11/3 [5] and the anisotropic factor is also used to describe the anisotropy of the atmosphere turbulence [6].…”

Section: Introductionmentioning

confidence: 99%

Wave Structure Function and Long-Exposure MTF for Gaussian-Beam Waves Propagating in Anisotropic Maritime Atmospheric Turbulence

Guan

¹

,

Yu

²

,

Song

³

et al. 2020

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The expressions of wave structure function (WSF) and long-exposure modulation transfer function (MTF) for laser beam propagation through non-Kolmogorov turbulence were derived in our previous work. In this paper, based on anisotropic maritime atmospheric non-Kolmogorov spectrum, the new analytic expression of WSF for Gaussian-beam waves propagation through turbulent atmosphere in a horizontal path is derived. Moreover, using this newly derived expression, long-exposure MTF for Gaussian-beam waves is obtained for analyzing the degrading effects in an imaging system. Using the new expressions, WSF and MTF for Gaussian-beam waves propagating in terrestrial and maritime atmospheric turbulence are evaluated. The simulation results show that Gaussian-beam waves propagation through maritime turbulence obtain more degrading effects than terrestrial turbulence due to the humidity and temperature fluctuations. Additionally, the degrading effects under anisotropic turbulence get less loss than that of isotropic turbulence.

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Intensity fluctuations of asymmetrical optical beams in anisotropic turbulence

Cited by 23 publications

References 38 publications

Anisotropy effect on multi-Gaussian beam propagation in turbulent ocean

Anisotropy effect on multi-Gaussian beam propagation in turbulent ocean

Spatial Property of Optical Wave Propagation through Anisotropic Atmospheric Turbulence

Wave Structure Function and Long-Exposure MTF for Gaussian-Beam Waves Propagating in Anisotropic Maritime Atmospheric Turbulence

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