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Photonic crystals for optoelectronic devices

We present results on the fabrication and characterization of two and one dimensional photonic crystals for optoelectronic device applications. By using high resolution electron beam lithography 2D and 1D photonic crystals structures are defined on GaAlAs/GaAs and InP/InGaAsP waveguide layers. A crucial step of the patterning is the dry etching, in which structures on a (sub) 100 nm scale with aspect ratios (width to height) of ten or more have to be obtained. We have realized straight waveguides, waveguides with sharp bends, waveguides with build - in cavities as well as lasers with 1D and 2 D photonic crystal mirrors. By using a build in quantum dot layer, optical modes in the passive structures can be investigated. In the InGaAsP as well as in the InGaAs material system ridge waveguide lasers with photonic crystal mirrors have been realized. For the InGaAs system 1D Bragg reflectors with reflectivities above 95 percent have been obtained. These mirrors are essential for mircolasers with active resonator length down to 12 micrometers . These are the shortest edge emitting lasers realized to date.