Numerical study of the supercontinuum generation in the telecommunications windows in photonic crystal fiber

This research explores a supercontinuum (SC) generation in silica based highly nonlinear photonic crystal fiber of near infrared window, suitable for application in the field of telecommunications [1]. Results obtained here could be of interest in attempts to improve the characteristics of multi-wavelength sources for dense wavelength division multiplexing (DWDM) systems. We study numerically SC dynamics in both spectral and temporal domain in three different optical windows, at referent wavelengths of 835nm, 1300nm and 1550 nm. The dependence of SC properties on the input pulse power, shape and the value of the chirp is investigated in details. It has been shown that the most intense spread of SC spectrum at fiber output is obtained in the third optical window, while the input signal shape, power and duration stayed unchanged [2]. The shape of the initial pulse was the most influential in the second optical window, where the simulated SC has flat and smooth profile, covering the wavelength range from 1000 nm to 2000 nm. In addition, we examine the SC spectrum coherence in all of the three optical windows with respect to different input pulses. On the other hand, the richest SC dynamics is observed in the first window, where the appearance of high intensity events of the rogue wave type is reported [3].VII International School and Conference on Photonics : PHOTONICA2019 : Abstracts of Tutorial, Keynote, Invited Lectures, Progress Reports and Contributed Papers; August 26-30; Belgrad

Strong coupling regime of semiconductor quantum dot embedded in the nano-cavity

Photonic lattices represent suitable systems for investigation of wave propagation in periodic structures [1]. However, different unavoidable defects may arise either during their process of fabrication or as result of misusage, accidental damage, etc. Although undesirable in the first place, these imperfections enable the existence of different types of stable, localized defect modes [2]. In this paper, we investigate light propagation through composite photonic lattice composed of two identical linear and lossless lattices. The interface between them represents a geometric defect, while each lattice contains a single nonlinear defect that is placed symmetrically with respect to the interface. Depending on the input light beam parameters (its position, width and transverse tilt), the width of geometric defect, strength and position of the nonlinear defects, different dynamical regimes have been identified. These dynamical regimes are caused by the balance of photonic lattice potentials’ contributions originating from the presence of the geometric and two nonlinear defects. We have found numerically conditions under which dynamically stable bounded modes can exist in the area between nonlinear defects or between a nonlinear and a geometric defect. Various types of localized modes such as: two-hump, multi-hump, one- and multicomponent moving breathers localized at a certain area among defects have been observed. The parameters can be adjusted to capture light and to prevent light launched inside the area among defects to leave it, i.e. this corresponds to the appearance of the modes trapped inside this area. Since the configuration of the lattice prevents transmission of the light through the area confined by defects, these modes can formally be related to Fano resonances and Fano- blockade [3, 4]. When light is launched outside the area among defects, different dynamical regimes have been distinguished: total reflection, single and double partial reflection and full transmission through the area among defects. These numerical findings may lead to interesting applications such as blocking, filtering and transporting light beams through the optical medium. Photonic devices based on resonant tunneling such as waveguides interacting through the area between defects, may be applied as add-drop filters.V International School and Conference on Photonics and COST actions: MP1204, BM1205 and MP1205 and the Second international workshop "Control of light and matter waves propagation and localization in photonic lattices" : PHOTONICA2015 : book of abstracts; August 24-28, 2015; Belgrad

Dynamics of electromagnetic solitons in a relativistic plasma

Dynamical features of one-dimensional electromagnetic solitons formed in a relativistic interaction of a linearly polarized laser light with underdense cold plasma are investigated. The relativistic Lorentz force in an intense laser light pushes electrons into longitudinal motion, generating coupled longitudinal-transverse waves. In a weakly relativistic approximation these modes are well described by the generalized nonlinear Schrodinger type of equation, with two extra nonlocal terms. Here, an original analytical solution for a moving electromagnetic soliton is derived in an implicit form. For an isolated soliton, our analysis shows that the motion downshifts the soliton eigenfrequency and decreases its amplitude. The effect of the soliton velocity on the stability is analytically predicted and checked numerically. Results show shifting of the stability region toward larger amplitudes in comparison to the standing soliton case. Rich dynamics with examples of (un)stable soliton propagation and breather creation and formation of unstable cusp-type structures is exposed numerically. (c) 2006 American Institute of Physics

Interaction of electromagnetic solitons in relativistic plasmas

Moving one-dimensional electromagnetic solitons formed in a weakly relativistic laser-plasma are studied in the generalized nonlinear Schroedinger equation model. Conserved quantities and moving soliton solutions are analytically derived in a closed form. Stability Studies reveal a transition at maximum amplitude to an unstable cusp-soliton. Simulations of two interacting electromagnetic (EM) solitons show a critical dependence on the solitons amplitude, velocity and mutual phase; resulting in either elastic collisions or a break up of the soliton pair.19th International Conference on Numerical Simulation of Plasmas/7th Asia Pacific Plasma Theory Conference, Jul 12-15, 2005, Nara, Japa

Numerical study of high intensity events in the supercontinuum generation in the presence of input chirp

We examine the supercontinuum (SC) dependence on the chirp of the input laser beam and effects of input pulse noise. Simultaneously, we investigate the relation between the SC generation and creation of localized high intensity events. We show that despite their low probability, these events inevitably appear in the SC in our setup. Their devastating role in the information transfer stimulates the research aiming for a deeper understanding of these phenomena which is of high importance in different fields of science, ranging from material science to telecommunications. This study can be considered as a step forward in tracing a route for controlling high intensity events. © 2019 Elsevier Gmb

Routing of optical beams by asymmetric defects in (non)linear waveguide arrays

Uniform one-dimensional (1D) nonlinear waveguide array, consisting of parallel, evanescently coupled waveguides represent a special case of 1D photonic crystal [1]. Matured fabrication procedures enable production of arrays whose intrinsic parameters (such as shape and dimensions of the waveguides, coupling strength between them, nonlinear response,…) may be easily changed. The possibility to manipulate light propagation through photonic crystals in a fully controllable fashion, have promise in the field of all-optical communications and photonic devices. However, unavoidable material imperfections, together with slight deviation during fabrication and misusage lead to existence of random defects in the system, which considerably hamper the control of the light flow. These imperfections enable the existence of different types of stable, localized defect modes (breathers and solitons [2]) which may be useful in routing, blocking and filtering of light. Interestingly, various defects may be intentionally inserted in uniform waveguide arrays, enabling studies of defect modes and their influence on light dynamics [3-5]. Interface of two semi-infinite waveguide arrays represent a type of structural (geometric) defect which also can host different localized modes [6, 7]. Recently, the influence of two nonlinear defects on light propagation through linear waveguide array [8] and the steering of discrete breathers in a linear lattice with two nonlinear defects [9] have been explored. Finally, light trapping, reflection and transmission near defect modes in composite linear photonic lattices have been investigated [10]. Here, we studied numerically (by split-step Fourier method) light beam propagation through either uniform of composite 1D (non)linear waveguide arrays having two asymmetric defects, a situation which can be fairly well modeled by the paraxial time-independent Helmholtz equation. Embedded asymmetric defects are either linear or nonlinear. Effects of different positions and widths of asymmetric defects on the light beam propagation have been examined and compared with a case of embedded symmetric defects. Various types of modes localized at these defects and in their vicinity have been found. We also have explored influence of asymmetric defects on tilted beam propagation and identify regimes of trapping, total reflection and transmission of light. Presented results provide an insight into the light beam dynamics in the presence of asymmetrical linear and nonlinear defects and might be useful in several all-optical applications such as filtering and steering of light beams through the optical medium.VI International School and Conference on Photonics and COST actions: MP1406 and MP1402 : PHOTONICA2017 : August 23 - September 1, 2017; Belgrade