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This paper presents the development of 3D fully self-consistent FEM Poisson and drift-diffusion solver. We use this solver to investigate the current flow in the coreshell multiple quantum well LED. The current spreading effect was examined to determine the carrier distribution at the sidewall of core-shell nanowire LEDs. The results revealed that a larger aspect ratio by increasing the nanowire height...
We present a time-domain traveling wave dynamic model for simulation of wavelength tunable three-section slotted Fabry-Perot semiconductor lasers. The slot structure is characterized by using the boundary conditions of the optical fields propagating through the slot facets. Static and dynamic wavelength switching characteristics are simulated. Good agreements have been found between the simulation...
We propose a novel infrared nanofilter of localized enhanced field with multiband resonant frequencies. Compared to the resonant wavelength, the structure size is very subwavelength. We establish the effective medium theory to illustrate the light field distribution of the fractals. The loss factor is used to retrieve relative permittivity which is utilized to reproduce of reflection and transmission...
We present the simulation results of a method for the quantum cascade detectors (QCD) optical coupling. A metal grating was integrated with a QCD to convert normal-incident electromagnetic (EM) waves into non-normal, higher-order propagating wave (HOPW) and surface plasmon wave (SPW), which contribute to excite the bound-to-bound (BTB) intersubband transition of carriers in the QCD. The presented...
In rigorous optical modeling and simulation of thin-film solar cells a few constraints and bottlenecks have been addressed recently. Two of them are related to how to include thick incoherent layers in the coherent finite element based simulations and how to describe and include non-conformal growth of layers in a thin-film solar cell. In this paper we present and apply three different solutions to...
Optomechanical nanocavities allow nanomechanical resonances to be measured optically with high sensitivity. We have created a new type of photonic crystal nanocavity optomechanical sensor optimized for detecting sources of torque and other forces which can deflect nanoscale cantilevers. This nanocavity consists of two precisely engineered photonic Bragg mirrors patterned in silicon cantilevers and...
Charge sensitive infrared phototransistors (CSIP) are well known for their capability for response spectrum tuning and single photon detection. In this paper, we established a physical model for a charge sensitive infrared phototransistor operating at 45μm wavelength using the Crosslight Apsys software. Several key physical mechanisms involved such as inter-subband optical transition and resonant...
Excessive depth of optically active quantum wells (QWs) in III-nitride light emitters of visible range is one of the main causes of inhomogeneous carrier injection in multiple-quantum-well (MQW) device active region. Deeper QWs imply stronger inhomogeneity of carrier distribution across the active region and support large residual charges of marginally located N-side and P-side QWs. Drift-diffusion...
The polarization splitting characteristics of a polarization beam splitter (PBS) based on two closely spaced parallel optical micro/nano-fibers (MNFs) were studied using the three dimension full vector beam propagation method (3-D FVBPM). Our results of the study show that a very compact PBS can be realized. Through numerical simulation, the geometric parameters of the PBS were optimally selected...
In this paper, we established a theoretical model and made an analysis of single knot-ring resonator by polarization transmission matrix. The theoretical analysis shows that two orthogonal polarization modes of knot-ring, which are originally resonant at the same wavelength, will be split into two resonant modes at two different wavelengths. The mode splitting owes to the twisted coupler of the knot-ring,...
We present atomistic simulations of InGaN quantum disk and quantum well structures considering randomly distributed In atoms. It is shown that the random alloy fluctuations lead to an intrinsic broadening of the optical emission lines with an asymmetric tail towards long wavelengths. The amount of broadening is found to be dependent on In content.
Metal-insulator-metal (MIM) circular grating structure has been introduced to couple with superconducting nanowire single-photon detector (SNSPD) to enhance its response. According to our numerical simulation results, the coupling efficiency at 1.55μm can be enhanced by MIM circular grating and improving the response of SNSPD obviously. About 19.5 times of enhancement in response can be obtained with...
In this talk, we will show some of the limitations of the finite difference technique when applied to k.p modeling of type II MQW structures. Improvements to the commercial APSYS software were made to overcome these limitations and provide sturdy rejection of spurious QW solutions. Dispersion relations and dipole moments for a sample GaAsSb/InGaAs structure will also be discussed.
We report on simulation results that shows optimum photon absorption by superconducting nanowires can happen at a fill-factor that is much less than 100%. We also present experimental results on high performance of our superconducting nanowire single photon detectors realized using NbTiN on oxidized silicon.
We present a numerical model of quasi one-dimensional and quasi zero-dimensional semiconductor heterostructures strictly based on experimental structures of polyphorm cylindrical nanocolumns.
We propose a novel excitable laser employing passively Q-switching with a graphene saturable absorber for spike processing networks. Our approach combines the picosecond processing and switching capabilities of both linear and nonlinear optical device technologies to integrate both analog and digital optical processing into a single hardware architecture capable of ultrafast computation without the...
Three-dimensional cold-cavity optical modes of oxide-confined AlGaAs/GaAs VCSELs at 850 nm were simulated taking into account the material dispersion to study dependencies of the lasing modal content upon the thickness of the aperture, its position with respect to the mode standing wave and the separation from the cavity. Positioning the thin aperture layer in the mode nodes to decrease the diffraction...
We demonstrate the slowing light effect by exciting the negative Goos-Hänchen effect originating from the fundamental degeneracy oscillatory mode within negative refractive waveguides (NRWs). In the work, we construct three kinds of metamaterial-base NRWs, including an anisotropic plasmonic waveguide operated at multiple incidences, a discrete dielectric metamaterial waveguide, and a monolithic tapered...
Linewidth and threshold calculations are made for a current-injected, partially 舖slotted’ semiconductor laser while including the effects of noise with an explicit derivation of photon-current coupling and varying reflectivities as a function of slot depth. Calculations are demonstrated to show good agreement with experiments.
We present a quasi-static model for the accurate simulation of swept source external cavity lasers. The model is based on steady-state solutions of multi-mode rate equations. The wavelength sweep is incorporated in the model by a spectral slicing technique. A comparison with experimental results demonstrates the usefulness of our approach. Limitations for the simulation of high-speed swept sources...
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