Reflectance anisotropy spectroscopy (RAS/RDS) has been used for basic growth studies in metal-organic vapor-phase deposition epitaxy (MOVPE). Because of its sensitivity for the uppermost atomic monolayers RAS is a suitable tool for the investigation of a variety of physical properties, such as surface stiochiometry and reconstruction. The enhanced performance of the EpiRAS measurement tool, made by LayTec, is suitable for MOVPE device growth monitoring and control in an industrial AIX 2600 G3 MOVPE reactor in the 8X4 inch configuration with gas foil rotation((R)). A brief introduction will be given to the basic surface physics and surface chemistry causing the optical signatures. Examples will be given concerning the optical, real time measurement of the growth of a GaAs/AlAs distributed Bragg reflector (DBR) and (AI(x)Ga(1-x))(0.5)In0.5P multi quantum well (MQW) laser structures. The results prove that in-situ monitoring of multi layer structures can be investigated in detail by RAS. The DBR was chosen to optimize the growth rate and thickness which was checked via X-ray data.