Browsing by Author "Freude, Wolfgang"

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Browsing by Author "Freude, Wolfgang"

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  • Koos, Christian; Fujii, Masafumi; Poulton, Christopher; Steingrueber, Ralf; Leuthold, Juerg; Freude, Wolfgang (IEEE Publications, 2006)
    The accuracy of nonlinear finite-difference time-domain (FDTD) methods is investigated by modeling nonlinear optical interaction in a ring resonator. We have developed a parallelized 3-D FDTD algorithm which incorporates ...
  • Koos, Christian; Poulton, Christopher; Zimmerman, L; Jacome, L; Leuthold, Juerg; Freude, Wolfgang (IEEE Publications, 2007)
    Bend designs for single-mode operation of low-loss overmoded waveguides are presented. A class of contour trajectories for minimum radiation loss is derived analytically, and numerical optimization is used to find ideal ...
  • Maitra, Ayan; Poulton, Christopher; Wang, Jin; Leuthold, Juerg; Freude, Wolfgang (IEEE Publications, 2005)
    We numerically study the nonlinear switching characteristics in a waveguide grating with a linearly tapered stopband. This type of design shows promising results in decreasing the threshold switching power, while simultaneously ...
  • Fujii, Masafumi; Koos, Christian; Poulton, Christopher; Leuthold, Juerg; Freude, Wolfgang (IEEE Publications, 2006)
    We demonstrate for the first time a nonlinear finite-difference time-domain (FDTD) analysis of optical parametric four-wave mixing (FWM) in an actual InGaAsP-InP-based racetrack microresonator, and the results are compared ...
  • Koos, Christian; Jacome, L; Poulton, Christopher; Leuthold, Juerg; Freude, Wolfgang (Optical Society of America, 2007)
    Values up to gamma = 7?106/(Wkm) for the nonlinear parameter are feasible if silicon-on-insulator based strip and slot waveguides are properly designed. This is more than three orders of magnitude larger than for ...
  • Fujii, Masafumi; Takashima, Tetsuya; Maitra, Ayan; Leuthold, Juerg; Freude, Wolfgang; Poulton, Christopher (Optical Society of America, 2007)
    Nonreciprocal optical bistability is numerically investigated in InGaAsP/InP nonlinear waveguide Bragg gratings having a strong and asymmetric sidewall modulation. Minimum switching power as low as 77 mW is predicted by ...
  • Fujii, Masafumi; Maitra, Ayan; Poulton, Christopher; Leuthold, Juerg; Freude, Wolfgang (Optical Society of America, 2006)
    We investigate numerically a non-reciprocal switching behavior in strongly modulated waveguide Bragg gratings (WBGs) having a longitudinally asymmetric stopband configuration. The minimum power predicted for a stable ...
  • Koos, Christian; Jacome, L; Poulton, Christopher; Leuthold, Juerg; Freude, Wolfgang (Optical Society of America, 2007)
    We numerically investigate the band structure and guided modes within arrays of metallic nanowires. We show that bandgaps appear for a range of array geometries and that these can be used to guide light in these structures. ...
  • Fujii, Masafumi; Omaki, N.; Tahara, Minoru; Sakagami, I.; Poulton, Christopher; Freude, Wolfgang; Russer, P. (IEEE Publications, 2005)
    We have investigated the parameter optimization for the nonlinear dispersive anisotropic perfectly matched layer (A-PML) absorbing boundary conditions (ABCs) for the two- and the three-dimensional (2D and 3D) finite-difference ...
  • Poulton, Christopher; Koos, Christian; Fujii, Masafumi; Freude, Wolfgang; Leuthold, Juerg; Pfrang, Andreas; Schimmel, Thomas (IEEE Publications, 2006)
    We predict the scattering loss in rectangular high index-contrast waveguides, using a new variation of the classical approach of coupled-mode theory. The loss predicted by this three-dimensional (3-D) model is considerably ...
  • Poulton, Christopher; Mueller, Manfred; Freude, Wolfgang (Optical Society of America, 2005)
    We present results from a new method for the solution of electromagnetic scattering from finite sets of two-dimensional cylinders exhibiting sidewall deformations. Our model treats the sidewall deviation as a small ...
  • Fujii, Masafumi; Koos, Christian; Poulton, Christopher; Sakagami, I.; Leuthold, Juerg; Freude, Wolfgang (Wiley Interscience, 2006)
    A rigorous quantitative verification technique is presented for nonlinear finite-difference time-domain (FDTD) algorithms by analyzing parametric four-wave mixing (FWM) in an optical Kerr medium without involving other ...
  • Poulton, Christopher; Wang, Jin; Maitra, Ayan; Freude, Wolfgang; Leuthold, Juerg (IEEE Publications, 2007)
    The temporal evolution of the alpha-factor during pump-probe experiments in semiconductor optical amplifiers (SOAs) is not constant but varies strongly with time. It even takes on negative values for short periods of time. ...