An electro-optical device includes a vertical cavity surface emitting laser, a heterojunction light emitting device and heterojunction phototransistor on a semiconductor substrate. Layers of the heterojuncticn phototransistor and the heterojunction light-emitting device are electrically and optically...http://www.google.fr/patents/US5666376?utm_source=gb-gplus-shareBrevet US5666376 - Electro-optical device
