16 research outputs found
Marcatili's Lossless Tapers and Bends: an Apparent Paradox and its Solution
Numerical results based on an extended BPM algorithm indicate that, in
Marcatili's lossless tapers and bends, through-flowing waves are drastically
different from standing waves. The source of this surprising behavior is
inherent in Maxwell's equations. Indeed, if the magnetic field is correctly
derived from the electric one, and the Poynting vector is calculated, then the
analytical results are reconciled with the numerical ones. Similar
considerations are shown to apply to Gaussian beams in free space.Comment: 4 pages, figures include
Theory of Slow Light Enhanced Four-Wave Mixing in Photonic Crystal Waveguides
The equations for Four-Wave-Mixing in a Photonic Crystal waveguide are
derived accurately. The dispersive nature of slow-light enhancement, the impact
of Bloch mode reshaping in the nonlinear overlap integrals and the tensor
nature of the third order polarization are therefore taken into account.
Numerical calculations reveal substantial differences with simpler models,
which increase with decreasing group velocity. We predict that the gain for a
1.3 mm long, unoptimized GaInP waveguide will exceed 10 dB if the pump power
exceeds 1 W.Comment: 6 pages, 4 figures; submitted to Optics Expres
Modeling of enhanced field confinement and scattering by optical wire antennas.
We describe the application of full-wave and semi-analytical numerical tools for the modeling of optical wire antennas, with the aim of providing novel guidelines for analysis and design. The concept of antenna impedance at optical frequencies is reviewed by means of finite-element simulations, whereas a surface-impedance integral equation is derived in order to perform an accurate and efficient calculation of the current distribution, and thereby to determine the equivalent-circuit parameters. These are introduced into simple circuits models, directly borrowed from radio frequency, which are applied in order to model the phenomena of enhanced field confinement at the feed gap and light scattering by optical antennas illuminated by plane waves