Waveguide/Photodetector Combination in SiGe for Long Wavelength Operation,

As silicon is a promising candidate for low cost integrated optical applications the monolithical integration of photodetectors is of major interest. Photodetectors for long wavelength operation have been realized on silicon as discrete devices and in combination with SOI-waveguides, having waveguide losses around 1dBcm. Recently, the losses of SiGe-waveguides already reported in could be reduced to O.5dBcm. In this work the efficient coupling between a SiGe-waveguide and a SiGe-detector is reported, which is a key component for integrated optics. Optical coherent applications, for example, then benefit from the low reflection coefficient at the waveguidephotodetector transition.