After a metal cap layer is laminated on a semiconductor laminated structure, a waveguide ridge is formed, the waveguide ridge is coated with an SiO2 film, and a resist is applied; then, a resist pattern is formed, the resist pattern exposing the surface of the SiO2 film on the top of the waveguide ridge,...http://www.google.se/patents/US20080090315?utm_source=gb-gplus-sharePatent US20080090315 - METHOD FOR MANUFACTURING SEMICONDUCTOR OPTICAL DEVICE
