We have grown lattice matched distributed Bragg reflectors (DBRs) based on up to 45 periods of AlInN and AlGaN lambda/4 layers designed for wavelengths at around 360 nm. The growth process was monitored by in-situ reflectance, temperature, and curvature measurements. The reflectance transients (at three different wavelengths) indicate smooth surfaces during the whole process and their appearance critically depends on the individual thicknesses of the DBR layers and thus on the stop-band position. By analyzing the beating of the transients, it was possible to determine the optical characteristics of the DBR already during growth. Since fluctuations of the growth rate can lead to unintentional changes of the stop-band position, the evaluation of the optical properties of the DBR can be used to adjust the growth parameters for the subsequent multiple quantum well, matching its emission wavelength to the bottom DBR. Additionally, the strain state within the structures was controlled by curvature measurements and the formation of cracks was prevented. Hence, DBRs exhibiting a maximum reflectance above 99% were realized. (C) 2012 Elsevier B.V. All rights reserved.