Index-guided semiconductor lasers having buried ridge waveguides which use the optical confinement resulting from the bandgap difference between a semiconductor material grown on the top plane of the ridge and a semiconductor material grown on the ridge's sidewalls. Beneficially AlGaInP is OMVPE formed...http://www.google.de/patents/US5465266?utm_source=gb-gplus-sharePatent US5465266 - Index-guided laser on a ridged (001) substrate
