The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
The aim of this work is an efficient implementation of a spatially resolved current spreading model defined in the vertical-lateral domain into a dynamic electro-optical solver acting in the longitudinal-lateral plane. We introduce two numerical methods for the solution of the current spreading model and perform test simulations using different approximations of the inhomogeneous current density along...
We model the situation of two lasers in a face to face arrangement, passing through an attenuating element, where the time of flight between the lasers is on the scale typical in photonic integration (100's of μm to mm's). A modified version of the Lang-Kobayashi equations was employed to describe the interaction. By solving this delay differential equation (DDE) system we characterised different...
We have developed a model of the nonlinear polariton dynamics in realistic strongly-coupled 3D non-planar microcavity wires based on driven-disspative mean-field Gross-Pitaevskii equations. We find that the typical microcavity nonlinear optical bistability response evolves into multistability upon variation of realistic model parameters and discuss its origin in terms of multiple co-existing transverse...
This paper presents an analysis of the material quality influence for amorphous silicon waveguides for microphotonic applications. Material quality is taken into account by a model based on the absorption coefficient data obtained by Constant Photocurrent Measurement (CPM) in the near infrared region. The GUTL (Gauss-Urbach-Tauc-Lorentz) model has been presented as an extension of the standard Urbach-Tauc-Lorentz...
We propose an accurate and robust in-phase/quadrature (IQ) skew measurement method for optical Mach-Zehnder IQ modulator based on image spectrum analysis. Numerical simulation and experiment results demonstrate 0.7ps measurement accuracy. The robustness to bias deviations and finite extinction ratios were also investigated.
Germanium-tin alloy (Ge1−xSnx), due to its direct gap nature for x > 0.08, has higher absorption coefficient than that of pure Ge. Using COMSOL Multiphysics, we have simulated the characteristics of Ge/GeSn/Ge heterojunction phototransistor, the base of which incorporates a multiple quantum well (MQW) structure made of Ge0.87Sn0.13 barrier and Ge0.75Sn0.155 well at a wavelength of 1.55 μm. The...
CONTROL of spontaneous emission itself is amongst the most intriguing and, at the same time, application-defining aspects of cavity-quantum electrodynamics (QED). In tailored dielectric structures, such as photonic crystal or micropillar cavities, light is confined to the cubic wavelength. Gain material embedded in such tiny mode volume interacts much more strongly with the electromagnetic field....
External optical feedback can influence semi-conductor laser performance to a great extent. Strong optical isolators with reasonable insertion loss are not available in a photonic integrated circuit due to material incompatibilities, preventing the use of an isolator external to the laser cavity to suppress any feedback effects. In this work the feedback sensitivity of a semiconductor ring laser with...
We present a novel kinetic Monte Carlo version for the atomistic valence force fields algorithm in order to model a self-assembled quantum dot growth process. We show our atomistic model is both computationally favorable and capture more details compared to traditional kinetic Monte Carlo models based on continuum elastic models. We anticipate the model will be useful to experimentalists in understanding...
In this work we have measured the far-field emission patterns of In As quantum dots embedded in a GaAs tapered nanowire and used an open-geometry Fourier modal method for determining the radial position of the quantum dots by computing the far-field emission pattern for different quantum dot locations.
A rate equation model was used to model the optical filtering properties of an injection locked semiconductor laser. The changes in the side mode suppression ratio (SMSR) of an injected optical comb due to the gain of the slave laser, and the frequency spacing of the injected optical comb, were investigated numerically. It was found that the SMSR increases with increasing gain in the slave laser,...
We propose a universal simulating solution to characterize the OIP3 of most kinds of photodetectors using Silvaco TCAD simulation tools. For a normal PIN photodetector and a unitraveling-carrier photodetector, a fine agreement was observed in experimental results and simulation results. We believe that this solution could be useful in designing and optimizing high-power photodetectors.
Thermalisation and below-bandgap loss mechanisms of intermediate band solar cells (IBSCs) comprised of InAs(1−x)Nx quantum dots (QDs) embedded within intrinsic layer of AlP0.5Sb0.5 p-i-n solar cell is calculated. a Finite element method is used for solving Schrödinger equation to calculate possible energy band configurations of AIP0.5Sb0.5: barrier/InAs(1−x)Nx: square pyramid-shaped QDs with different...
We review the progress in modeling of charge transport in disordered organic semiconductors on various length-scales, from atomistic to macroscopic. This includes evaluation of charge transfer rates from first principles, parametrization of coarse-grained lattice and off-lattice models, and solving the master and drift-diffusion equations. Special attention is paid to linking the length-scales and...
Oue to the wide adjustable range of bandgap and large exciton binding energy, InGaN/GaN nanowire quantum dots (NQDs) has been one of the most promising candidates for site-controlled single photon source (SPS) in a wide range from visible to near-infrared. Here the annular-grating-patterned hyperbolic metamaterials was proposed to enhance the performance of InGaN/GaN NQDs SPS. By combining the broadband...
In this paper, the structural model and the physical model of GaAs-based BIB THz detectors are constructed by means of numerical simulation. The effect of acceptor concentration on the dark current characteristics is investigated. Additionally, the optimal acceptor concentration corresponding to the maximum detectivity has been discussed from the application point of view.
The hybrid plasmonic photonic WGM modes of a metal coated microsphere resonator are numerically investigated. The proposed geometry consists of a three-layer structure with a silica microsphere core, a 30 nm silver intermediate layer and an outer polymer layer. It has been shown that the proposed geometry supports hybrid resonances with moderately high Q-factor and low mode volume. The properties...
We numerically demonstrate dispersion tailoring of a silicon strip waveguide employing Titania-Alumina thin-film coating using a finite-difference mode solver. The proposed structure exhibits spectrally-flattened near-zero anomalous dispersion within the telecom wavelength range. We also numerically predict the wavelength conversion efficiency for degenerate four-wave mixing, and obtain a 3 dB bandwidth...
In this paper, nanobeam cavity studies were performed on low-symmetric 1D photonic crystals. An eligible comparison between low-symmetric structure and a regular cavity is held. Due to nature of the resonance, reduced symmetry is expected to decrease confined resonance field; however, authors focused on the tuning of the extra parameters arisen from degenerated symmetry and promising results are obtained...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.