All silicon electrooptic devices for modulating and switching of guided light have been developed using the silicon-on-insulator approach. Generally, p-n junctions are formed in a silicon waveguide to selectively modulate and direct light by carrier refraction. An electrooptic phase modulator and several...http://www.google.de/patents/US4787691?utm_source=gb-gplus-sharePatent US4787691 - Electro-optical silicon devices
