The Experts below are selected from a list of 34452 Experts worldwide ranked by ideXlab platform

H A Illias - One of the best experts on this subject based on the ideXlab platform.

  • the influence of spherical Cavity Surface charge distribution on the sequence of partial discharge events
    Journal of Physics D, 2011
    Co-Authors: H A Illias, G Chen, P L Lewin
    Abstract:

    In this work, a model representing partial discharge (PD) behaviour of a spherical Cavity within a homogeneous dielectric material has been developed to study the influence of Cavity Surface charge distribution on the electric field distribution in both the Cavity and the material itself. The charge accumulation on the Cavity Surface after a PD event and charge movement along the Cavity wall under the influence of electric field magnitude and direction has been found to affect the electric field distribution in the whole Cavity and in the material. This in turn affects the likelihood of any subsequent PD activity in the Cavity and the whole sequence of PD events. The model parameters influencing Cavity Surface charge distribution can be readily identified; they are the Cavity Surface conductivity, the inception field and the extinction field. Comparison of measurement and simulation results has been undertaken to validate the model.

  • The effect of spherical Cavity Surface charge distribution on the sequence of PD events
    2011
    Co-Authors: H A Illias, G Chen, Paul Lewin
    Abstract:

    Modelling of partial discharge (PD) events allows a better understanding of the phenomena itself. In this work, an improved model representing PD behaviour within a spherical Cavity in a homogeneous dielectric material has been developed to study the influence of Cavity Surface charge distribution on the electric field distribution in the Cavity. Comparison of measurement and simulation results has been undertaken to validate the model. The model uses a two-dimensional axial symmetric Finite Element Analysis method, which is solved for local electric potentials. The model geometry consists of a homogenous dielectric material and a spherical Cavity. The upper and lower Cavity Surfaces are divided into 10 boundaries each to model charge distribution along the Cavity wall. Discharge is assumed to occur along the symmetry axis in the Cavity. Once the discharge has passed through the Cavity to the opposite Surface, it is assumed that charge then propagates along the upper and lower Cavity Surfaces. Charge distribution is assumed symmetrical on the upper and lower Cavity Surfaces. During discharge, charge density increases on the Cavity Surface boundaries where charge propagates, until the field in the Cavity centre is less than the extinction field. To model the charge movement along the Cavity wall through conduction at other times, the change in the charge density on each Cavity Surface boundary is set as dependent on the Cavity Surface conductivity. Thus, Cavity Surface charge distribution will influence the electric field distribution in the Cavity, affecting the likelihood of the next PD event.

P L Lewin - One of the best experts on this subject based on the ideXlab platform.

  • the influence of spherical Cavity Surface charge distribution on the sequence of partial discharge events
    Journal of Physics D, 2011
    Co-Authors: H A Illias, G Chen, P L Lewin
    Abstract:

    In this work, a model representing partial discharge (PD) behaviour of a spherical Cavity within a homogeneous dielectric material has been developed to study the influence of Cavity Surface charge distribution on the electric field distribution in both the Cavity and the material itself. The charge accumulation on the Cavity Surface after a PD event and charge movement along the Cavity wall under the influence of electric field magnitude and direction has been found to affect the electric field distribution in the whole Cavity and in the material. This in turn affects the likelihood of any subsequent PD activity in the Cavity and the whole sequence of PD events. The model parameters influencing Cavity Surface charge distribution can be readily identified; they are the Cavity Surface conductivity, the inception field and the extinction field. Comparison of measurement and simulation results has been undertaken to validate the model.

Dieter Bimberg - One of the best experts on this subject based on the ideXlab platform.

  • Metal-Cavity Surface-Emitting Nanolasers
    IEEE Journal of Quantum Electronics, 2020
    Co-Authors: Chien-yao Lu, Shun Lien Chuang, Dieter Bimberg
    Abstract:

    A new type of Surface-emitting nanolasers with a metal Cavity is proposed and analyzed for potential use in future optical interconnects. Rather than using the Surface mode of the metallic waveguide, the design uses the low-loss optical fiber HE11 mode. An analytical Fabry-Perot model is formulated to include the nanoCavity effect. A numerical model based on the FDTD method is also used to confirm our analytical model and illustrate the major physics and important optimization principles. The model is also used to analyze the Cavity modes of quantum-dot metal-Cavity Surface-emitting microlasers with the results agreeing very well with the experimental data.

  • Metal-Cavity Surface-emitting micro/nanolasers
    IEEE Winter Topicals 2011, 2011
    Co-Authors: Shun Lien Chuang, Chien-yao Lu, Shu-wei Chang, T. D. Germann, Udo W. Pohl, Dieter Bimberg
    Abstract:

    Theory and experiment of nanoscale metal-Cavity Surface-emitting lasers using multiple quantum wells with continuous-wave operation at room temperature are presented.

  • Characteristics of metal-Cavity Surface-emitting microlaser
    Photonics, 2010
    Co-Authors: Chien-yao Lu, Shun Lien Chuang, Shu-wei Chang, T. D. Germann, Udo W. Pohl, Dieter Bimberg
    Abstract:

    We demonstrate a metal-Cavity Surface-emitting microlaser with sub-angstrom linewidth and an output power exceeding 7 microwatt. The device shows CW room-temperature single-mode operation up to 4 microwatt and a 1.2 nm-wavelength shift with increased current.

  • Polarization Switching in Quantum-Dot Vertical-Cavity Surface-Emitting Lasers
    IEEE Photonics Technology Letters, 2009
    Co-Authors: Lukasz Olejniczak, Hugo Thienpont, Marc Sciamanna, Krassimir Panajotov, Alex Mutig, Friedhelm Hopfer, Dieter Bimberg
    Abstract:

    We demonstrate experimental evidence of polarization switching accompanied by polarization-mode hopping in quantum-dot vertical-Cavity Surface-emitting lasers. In our case, the polarization switching is associated with a change of linearly polarized light to elliptically polarized one, hence switching takes place between elliptically polarized states. Current-modulation measurements show that the polarization switching is of thermal origin.

Kent D. Choquette - One of the best experts on this subject based on the ideXlab platform.

  • Planar Photonic Crystal Vertical-Cavity Surface-Emitting Lasers
    IEEE Journal of Selected Topics in Quantum Electronics, 2013
    Co-Authors: A. M. Kasten, J.d. Sulkin, Kent D. Choquette
    Abstract:

    Planar index-guided proton-implanted photonic crystal vertical-Cavity Surface-emitting lasers are fabricated and characterized. Index guiding from the photonic crystal improves the performance of the lasers by creating a stable light output versus current response, reducing the threshold current, and enhancing the differential quantum efficiency. Examination of the etch depth dependence of laser efficiency reveals various mechanisms that affect the laser performance and modal properties such as optical loss, Joule heating, and spectral gain-resonance alignment. Photonic crystal designs can be chosen which result in lasing operation only in the fundamental transverse mode from threshold to maximum power, even for the condition of blue-shifted gain spectrum relative to the Cavity resonance. Suitable photonic crystal designs are shown to be manufacturable due to the planar device topology, the use of optical lithography in all processing steps, and compatibility with virtually any vertical-Cavity Surface-emitting laser epitaxial designs.

  • Passive Cavity Surface emitting laser
    Electronics Letters, 2011
    Co-Authors: James A. Lott, V. A. Shchukin, N. N. Ledentsov, A. M. Kasten, Kent D. Choquette
    Abstract:

    Demonstrated is a vertical Cavity Surface emitting laser (VCSEL) formed by a passive half-wavelength Cavity and a quarter-wavelength active gain region, wherein the said gain region resides in one of the VCSEL's distributed Bragg reflectors. The device concept invites extensive opportunities for innovation in the combinations of materials and gain region placements that may be used to construct Surface emitting devices.

  • Analysis of coupled vertical-Cavity Surface-emitting laser arrays
    Conference on Lasers and Electro-Optics 2010, 2010
    Co-Authors: Dominic F. Siriani, A. C. Lehman Harren, Paul Scott Carney, Kent D. Choquette
    Abstract:

    Coupling properties of vertical-Cavity Surface-emitting laser (VCSEL) arrays are analyzed using a new stochastic coupled mode theory. Comparisons between theory and experiment reveal important details about the coupling and coherence of VCSEL arrays.

  • Small pitch vertical Cavity Surface emitting laser arrays
    2004
    Co-Authors: E.w. Young, Kent D. Choquette
    Abstract:

    We show that mesa-isolated top emitting selectively oxidized 850 nm vertical Cavity Surface emitting lasers can be fabricated with 21 /spl mu/m separation with minimal thermal crosstalk.

  • coupled defect photonic crystal vertical Cavity Surface emitting lasers
    Electronics Letters, 2003
    Co-Authors: Aaron J Danner, J J Raftery, Noriyuki Yokouchi, Kent D. Choquette
    Abstract:

    Photonic crystal patterns containing two defects were fabricated within a large gain area in vertical Cavity Surface emitting lasers. By designing effective refractive index changes in the region between the defects through Cavity shifts caused by photonic crystals, it was possible to coherently couple laser light output from the defects. This enables a novel way to fabricate coherently coupled laser arrays.

G Chen - One of the best experts on this subject based on the ideXlab platform.

  • the influence of spherical Cavity Surface charge distribution on the sequence of partial discharge events
    Journal of Physics D, 2011
    Co-Authors: H A Illias, G Chen, P L Lewin
    Abstract:

    In this work, a model representing partial discharge (PD) behaviour of a spherical Cavity within a homogeneous dielectric material has been developed to study the influence of Cavity Surface charge distribution on the electric field distribution in both the Cavity and the material itself. The charge accumulation on the Cavity Surface after a PD event and charge movement along the Cavity wall under the influence of electric field magnitude and direction has been found to affect the electric field distribution in the whole Cavity and in the material. This in turn affects the likelihood of any subsequent PD activity in the Cavity and the whole sequence of PD events. The model parameters influencing Cavity Surface charge distribution can be readily identified; they are the Cavity Surface conductivity, the inception field and the extinction field. Comparison of measurement and simulation results has been undertaken to validate the model.

  • The effect of spherical Cavity Surface charge distribution on the sequence of PD events
    2011
    Co-Authors: H A Illias, G Chen, Paul Lewin
    Abstract:

    Modelling of partial discharge (PD) events allows a better understanding of the phenomena itself. In this work, an improved model representing PD behaviour within a spherical Cavity in a homogeneous dielectric material has been developed to study the influence of Cavity Surface charge distribution on the electric field distribution in the Cavity. Comparison of measurement and simulation results has been undertaken to validate the model. The model uses a two-dimensional axial symmetric Finite Element Analysis method, which is solved for local electric potentials. The model geometry consists of a homogenous dielectric material and a spherical Cavity. The upper and lower Cavity Surfaces are divided into 10 boundaries each to model charge distribution along the Cavity wall. Discharge is assumed to occur along the symmetry axis in the Cavity. Once the discharge has passed through the Cavity to the opposite Surface, it is assumed that charge then propagates along the upper and lower Cavity Surfaces. Charge distribution is assumed symmetrical on the upper and lower Cavity Surfaces. During discharge, charge density increases on the Cavity Surface boundaries where charge propagates, until the field in the Cavity centre is less than the extinction field. To model the charge movement along the Cavity wall through conduction at other times, the change in the charge density on each Cavity Surface boundary is set as dependent on the Cavity Surface conductivity. Thus, Cavity Surface charge distribution will influence the electric field distribution in the Cavity, affecting the likelihood of the next PD event.