WAVES AND VIBRATIONS IN INHOMOGENEOUS STRUCTURES ...

waveguides have inherently lower propagation losses than the photonic crystal waveguides, and may be
alternatives/supplements to these in future photonic integrated circuits.
Our topology optimization algorithm is based on a two-dimensional finite element model of the
Helmholtz equation that models propagation of plane polarized light. The finite element model is used
to compute the energy transmission through the waveguides and the optimization algorithm is used to
redistribute air and dielectric in the trouble regions in order to maximize the transmission. A SIMP-like
material model is used together with analytical sensitivity analysis and the mathematical programming
software MMA. We use a penalization method based on artificial damping (PAMPING) to ensure a
feasible binary design, and perform optimization for several frequencies by exploiting fast-frequencysweeps
using Padé approximants.
The photonic wire components are currently being analyzed using a 3D finite-difference-time-domain
code and will soon be tested experimentally. Additionally, other components such as a wavelength splitters
in photonic crystal and photonic wire waveguides are currently being developed as well as directional
couplers. Future research include also optimization based on 3D finite element models.
7. References
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