Single-mode vertical-cavity surface-emitting lasers grown under accurate real-time optical control

Summary form only given. We applied an optical real-time growth control technique: TDOR (tunable dynamic optical reflectometry) to grow GaAs/AlGaAs-based VCSELs. TDOR control consists of exploiting reflectivity interferences measured on the growing multilayer with a tunable optical source. Prior to the growth, a set of optimal wavelengths corresponding to the successive layers to be controlled, is calculated within the tunable laser emission range. For each optimal wavelength, a reflectivity extremum is observed when the aimed corresponding layer thickness is attained, thus allowing a direct use of the reflectometry signal for effusion cells shutters synchronisation. For VCSELs, the influence of both the QWs in the cavity and the numerous graded composition layers inserted at each DBR interface have been taken into account in TDOR modelling, as well as the different substrate temperatures applied during growth. After growth, the structures have been processed using RIE to define mesas, BCB for planarization and finally selective lateral oxidation of an AlAs layer near the cavity in order to form a buried oxide aperture.