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Photonic crystals are structures which consist of various dielectric
materials with a periodicity of the order of the photonic wavelength.
This could lead to very small integrated optical devices. These
structures exhibit a range of forbidden optical frequencies, which
is called a photonic band gap. Photonic crystals could lead to very
small integrated optical devices. The research on possible applications
of photonic crystals can be divided into two main categories:
| (i) |
Control of the spontaneous emission, e.g., inhibition
or enhancement of spontaneous emission, nearly thresholdless
laser action, strongly directed emission and spectral narrowing
of otherwise broad emission. |
| (ii) |
Various potential device applications to build
dense optical circuits are imaginable. It has been shown that
ultrasmall bending radii of waveguide bends and ultrasmall microcavities
are possible. This could lead to very compact mode couplers,
superprisms, WDM add-drop filters and dispersion compensators.
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To investigate the possibilities of photonic crystals we employ
theoretical and experimental methods and focus of the on two-dimensional
photonic band-gap structures consisting of silicon and its oxides
(SOI as well as SiON). Theoretical calculations are performed to
design and obtain the stationary and temporal behavior of the photonic
band-gap structures. For the experimental investigations we exploit
synergies with our colleagues in the photonic, organic LED and microcontact
printing groups. Furthermore, we utilize IBM's microfabrication
skills. Intrinsic light sources are employed to characterize the
optical properties of the fabricated nanostructures. Experimentally,
one of the key issues is that uniformity and irregularities in fabricated
structures will limit the quality factor.
 Schematic
view (right) of a waveguide in triangular photonic band-gap
slab realized in SOI, where the pink layer indicates silicon and
the blue layers indicate silicon-dioxide.
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