Analyzing the propagation behavior of scintillation index and bit error rate of a partially coherent flat-topped laser beam in oceanic turbulence

Abstract

In this paper, on the basis of the extended Huygens-Fresnel principle, a semianalytical expression for describing on-axis scintillation index of a partially coherent flat-topped (PCFT) laser beam of weak to moderate oceanic turbulence is derived; consequently, by using the log-normal intensity probability density function, the bit error rate (BER) is evaluated. The effects of source factors (such as wavelength, order of flatness, and beam width) and turbulent ocean parameters (such as Kolmogorov microscale, relative strengths of temperature and salinity fluctuations, rate of dissipation of the mean squared temperature, and rate of dissipation of the turbulent kinetic energy per unit mass of fluid) on propagation behavior of scintillation index, and, hence, on BER, are studied in detail. Results indicate that, in comparison with a Gaussian beam, a PCFT laser beam with a higher order of flatness is found to have lower scintillations. In addition, the scintillation index and BER are most affected when salinity fluctuations in the ocean dominate temperature fluctuations.

Impact of Turbulent-Flow-Induced Scintillation on Deep-Ocean Wireless Optical Communication

“…In their research, different probability density functions (PDFs) are used to describe the statistical distribution of different types of turbulence, and the statistical scintillation data was measured. Recent models focus on the relationship between the RI and the thermohaline distribution [17,18]. Thermohaline diffusivities have an impact on the dissipation rate, and most importantly, these diffusivities are not constant in the presence of turbulence.…”

Scintillation and BER analysis of the partially coherent flat-topped array laser beam in the non-Kolmogorov atmospheric turbulence on slant path

“…The fourth-order moment can theoretically be used to predict the correlation width of the irradiance fluctuations and the scintillation index [1][2][3]. Generally, in applications such as astronomical and oceanic imaging, remote sensing, and optical communications that require the transmission of modulated laser beams through the turbulent media such as atmosphere and ocean, the scintillation causes signal fading, degrades the signal-to-noise ratio (SNR), and results in a higher bit error rate (BER) [12,16,17,32]. Thus, knowledge of optical scintillation under various media conditions is highly desirable.…”

“…Moreover, finding a good solution to overcome the destructive effects of turbulence and consequently increase in quality of the communication link parameters in FSO systems is an engaging topic that has attracted theoretical and experimental researchers' attentions [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19].…”

“…To eliminate the destructive effect of scintillation on laser beam transmission, different methods, such as increasing receiver aperture size, making phase correction via adaptive optics, using different laser beam such as different shape (Gaussian beam, Flat-topped beam, array beam,...) and different spatial coherence (partially and fully coherent laser beam), have been used in turbulent media [12,13,16,17,[20][21][22][23][24].…”

Ber of Annular Beams in Weak Oceanic Turbulence

“…The propagation of various kind of laser beams used in wireless optical links in underwater channels will cause intensity fluctuations, also affect the performance of optical communication link (Kumar et al, 2011;Lu et al, 2006;Korotkova et al, 2012;Baykal, 2015;Yousefi et al, 2015;Yi et al, 2015;Gökçe et al, 2016;Baykal, 2016;Cheng et al, 2016;Peng et al, 2017;Nikishov and Nikishov, 2000;Gerçekcioglu, 2014;Ata and Baykal, 2014). Especially, the scintillation indices of optical plane and spherical and Gaussian beams propagating in underwater turbulent media are researched by using the Rytov method (Gerçekcioglu, 2014;Ata and Baykal, 2014).…”