On the route towards Si-based optical interconnects
We have developed and fabricated a prototype of optical interconnects on a Si substrate. The original device design includes an aluminumporous silicon light-emitting diode connected with a photodetector by an alumina waveguide. In order to minimize optical losses, the waveguide has been realized by subsequent deposition of three aluminum layers among which the intermediate one was doped with a titanium large refractive index layer. This multilayer structure was then anodically oxidized to form an Al2O3/Al2O3+TiO2/Al2O3 layered waveguide. In the integrated optoelectronic unit it provides up to 50% increase of the detector response with respect to a waveguide of pure Al2O3. Optical losses in the visible range have been estimated to be about 1 dB/cm. Another method for increasing the detector response through the use of a microcavity is discussed.
optical interconnects electrochemical anodizing porous silicon porous alumina