The lasing peak of lambda = 1090 nm at T = 110 K was obtained for a microdisk cavity with three layers of InGaAs quantum dots integrated on AlAs/GaAs distributed Bragg reflector. The refractive indices and reflectance spectrum of AlAs/GaAs DBR at T = 110 K were derived and estimated. The lasing mode was subsequently confirmed as the whispering gallery mode with azimuthal mode number m = 13 and could be explained as the valid of bottom DBR mirror. (c) 2013 Elsevier B.V. All rights reserved.