Search

In this study, we investigate Airy, cos-Airy, and cosh-Airy beam lasers with optical vortex (OV). Then, taking into account the Fourier transform, we examine and compare the propagation of these beams in a strong nonlinear system. The results indicate that by changing the input power p 0 and the parameters b and propagation length, the location of OV displaces. It is shown that nonlinearity is one of the parameters that control OV in optical systems used in these types of lasers. An important property in these beams is their direction variation due to the change in the mentioned parameters, which can be used in applications such as beam switching. [ABSTRACT FROM AUTHOR]

Today, one of the most important objectives concerned with integrated optical circuits is to realize all-optical networks. High transmission speed and efficiency and no interference between optical and electronic signals encourage us to manufacture all-optical devices. In the present paper, photonic analog-to-digital converters that are one of the key structures required in integrated optical circuits have been investigated. One of the advantages of these converters is the generation of binary codes, which leads to faster data transfer. In all the proposed designs, a power and wavelength discretizer and a coder have been used to find the optimal structure with the best specifications. The optical discretizer located at the input and designed as a combination of rods and ring resonators is strongly influenced by the input power due to nonlinear effects. The coder structure that consists of input and output ports can be controlled by controlling such elements as radius and refractive index and sometimes creating cavities in the structure. Reviewing the relevant literature can make it clear that a delay time of 5 ps and a footprint of 1520 μm can be achieved by controlling the resonance modes. By creating a cavity in the proposed design, an operation speed of 1 Ts and a footprint of 42 µm2 can be achieved, causing significant improvements compared to previous designs. For better transmission, additional GaN ring resonators can be placed in the structure so that it can support the sampling rate of 220 GS/s with a resolution of 880KS. By adjusting the coupling coefficients in the structures, the threshold level can also be adjusted. These coefficients depend on the radius and refractive index. The improved optical ADC operation and switching speed and the reduced power consumption can be realized by adjusting them. In structures where the binary code “11” is generated, a sampling time of 1.5 ps can be achieved using a number of optical switches. Such converters are designed with a square and triangular topology using dielectric rods in the air (or air rods in dielectric) with a certain lattice constant and filling ratio. The Finite-difference time-domain (FDTD) method is used to simulate these structures. [ABSTRACT FROM AUTHOR]

In this paper, we have theoretically investigated the behaviour of an Airy beam (AiB) with an optical vortex (OV) in atmospheric turbulence. The obtained splitting on each line of the phase pattern indicates the OV. The results show that the OV position changes when the power of the fractional Fourier transforms (FrFT) ( p ) changes. Moreover, uniformity of the spot beam disappears with the presence of the vortex in the AiB. The characteristics of an AiB, such as the effective beam size, number, width, height, and uniformity of the spot beam, change by changing the value of p . The position of the OV in the beam with scintillation and without scintillation was changed by changing the value of p . [ABSTRACT FROM AUTHOR]

Functionality and spatial concentration of light in periodic and disordered plasmonic crystal metallic nanowires are investigated under Kerr nonlinearity. The results show that nonlinear transverse localization of surface plasmon polaritons (SPP) in a periodic and disordered array of nanowires embedded in the Kerr medium changes with incident input wave amplitude (A). We study periodic and diagonal disordered nanowire arrays and study the propagation of SSPs under different inputs by solving nonlinear coupling relations. Finally, off-diagonal disordered nanowire arrays are studied. The results show that localization and effective beamwidth of the SPPs increases with an increase in their input amplitudes. Also, the SPPs become more localized with increase of diagonal (δr) and off-diagonal disorder (δd) into the nanowire arrays. Controlling SSPs' localization in the nanowire array using their input amplitude provides a high functional sub-wavelength device that can be utilized in future applications of nanophotonics functions. • Nonlinear properties of system of embedded metallic nanowires in Kerr medium is studied. • Localization of surface plasmon polaritons (SPP) change with incident intensity. • Transverse effective beamwidth is controlled by input intensity. • Controlling of SPP provide functional sub-wavelength device. • The results can be utilized in future of nanophotonic functions. [ABSTRACT FROM AUTHOR]