In this paper, on the basis of extended Huygens-Fresnel principle, a semianalytical expression for describing on-axis scintillation index partially coherent flat-topped (PCFT) laser beam weak to moderate oceanic turbulence is derived; consequently, by using log-normal intensity probability density function, bit error rate (BER) evaluated. The effects source factors (such as wavelength, order flatness, and width) turbulent ocean parameters Kolmogorov microscale, relative strengths temperature...

In this paper, the performance of underwater wireless optical communication (UWOC) links, which is made up partially coherent flat-topped (PCFT) array laser beam, has been investigated in detail. Providing high power, beams are employed to increase range UWOC links. For characterization effects oceanic turbulence on propagation behavior considered using extended Huygens–Fresnel principle, an analytical expression for cross-spectral density matrix elements and a semi-analytical one...

Using an integrated colliding-pulse mode-locked semiconductor laser, we demonstrate the existence of nonlinear dynamics and chaos in photonic circuits (PICs) by demonstrating a period-doubling transition into chaos. Unlike their stand-alone counterparts, PICs are more stable over lifetime system, reproducible from batch to on faster time scales due small sizes PICs.

Abstract This paper presents a scheme of terahertz radiation generation based on beating two dark hollow laser beams with different frequencies, the same electric field amplitudes, in actual plasma spatially periodic density that electron–neutral collisions have taken into account. The main feature considered is, having power at beam orders. Because special distribution intensity gradient beam, produced has profile. effects and parameters are investigated analytically. It can be deduced by...

In this experimental research, the effects of refractive index fluctuations resulting from temperature on some most important underwater communication link parameters such as average received power, signal to noise ratio (SNR) and normalized power variance (aperture averaged scintillation) has been experimentally investigated. Moreover, by introducing a new probability density function which is fitted more appropriately data obtained our simulator tank, bit error rate (BER) behavior an...

This paper presents a laboratory study of the aberrations calculation in underwater turbulence using Shack-Hartmann wavefront sensor. The decomposition method and Zernike polynomials determine aberration parameters. In our experimental setup, turbulent phase screen generator is located two locations: near transmitter therefore far from receiver, receiver consequently transmitter. Additionally, we investigate impact aperture diameter on turbulence-induced optical system. However, it essential...

In this research, an analytical expression for cross-spectral density matrix elements (and consequently, average intensity) of partially coherent flat-topped (PCFT) radial array laser beams in weak oceanic turbulence are derived based on the extended Huygens–Fresnel principle and previously developed knowledge propagation a beam atmosphere. Mean-squared width is calculated analytically using intensity formula. The simulation done by considering effects source parameters (such as radius...

In the present paper, a scheme for generation of terahertz (THz) radiation in electron-neutral collisional plasma based on beating two Gaussian laser array beams has been proposed. It is shown that efficiency THz can be enhanced drastically comparison with one. Furthermore, producing by beams, which an exclusive field profile, affected some structure parameters. also used to overcome negative consequences electron neutral collisions plasma, may occurring process. Optimizing and parameters,...

In this research, based on an analytical expression for cross-spectral density (CSD) matrix elements, coherence and polarization properties of phase-locked partially coherent flat-topped (PCFT) radial array laser beams propagating through weak oceanic turbulence are analyzed. Spectral degrees analytically calculated using CSD elements. Also, the effective width spatial degree (EWSDC) is numerically. The simulation done by considering effects source parameters (such as radius setup's circle,...

Theoretical study of propagation behaviour partially coherent divergent Gaussian beams through oceanic turbulence has been performed. Based on the previously developed knowledge a beam in atmosphere, spatial power spectrum refractive index ocean water, extended Huygens–Fresnel principle and unified theory coherence polarization, analytical formulas for cross-spectral density matrix elements are derived. The intensity distribution, width spectral degree determined by using elements. Then,...

Scientists have been improving the aerodynamic performance of flapping micro aerial vehicles by drawing inspiration from birds and insect flight. In this research study, first, mechanism black-headed gull is designed then it constructed in order to investigate effects wing bending deflection on performance. Thrust generation, power consumption loading are considered as parameters. Three wings representing different underlying structures, namely flexible membrane, rigid membrane airfoil,...

Free-space optical communication systems are affected by turbulent atmosphere. The atmospheric transmission is absorption, scattering and turbulence. In this paper, the effects of absorption taken into account using Beer’s law turbulence considered in calculating average intensity distribution. An analytical expression for distribution a partially coherent flat-topped array (PCFTA) beam atmosphere derived based on extended Huygens–Fresnel principle. intensity, power bucket, signal to noise...

In this paper, on the basis of extended Huygens-Fresnel principle, a semi-analytical expression for describing on-axis scintillation index partially coherent flat-topped laser beam through non-Kolmogorov maritime and terrestrial atmospheric environments slant path is derived. Consequently, by using log-normal intensity probability density function, bit error rate (BER) evaluated. The effects source factors (such as wavelength, order flatness, width) turbulent atmosphere parameters Kolmogorov...

Abstract This paper presents a scheme of terahertz (THz) radiation generation based on beating two flat-topped laser beams by different frequencies and the same electric field amplitudes in actual plasma with spatially periodic density that electron–neutral collisions have been taken into account. Flat-topped exclusive features such as steep gradient distribution intensities, wider cross-section comparison other profiles, which make stronger ponderomotive force lead to nonlinear current...

In this paper, we experimentally report the saturated absorption spectroscopy (SAS) and frequency locking (FL) of a narrow-band DBR laser with 0.5MHz linewidth on LD2-transition Rb atoms.