Patent ID: 7545560

Claim:
A distributed Bragg reflector (DBR) comprising: a plurality of AlAs regions that comprise a layer of AlAs; wherein the plurality of AlAs regions includes a first AlAs region and a second AlAs region; a plurality AlGaAs regions alternating with the AlAs region, wherein at least one AlGaAs region is a composite comprising: a plurality of thin AlAs layers and a plurality of thin GaAs layers, wherein the thin AlAs layers and the thin GaAs layers are each essentially homogenous; and the plurality of thin GaAs layers alternating with the plurality of thin AlAs layers, wherein each of the plurality of thin AlAs layers and each of the plurality of thin GaAs layers are between 10 and 100 Angstroms thick, such that the alternating thin layers of AlAs and the alternating thin layers of GaAs together form an AlGaAs region; wherein the composite AlGaAs region adjoins the first AlAs region beneath the first AlAs region and adjorns the second AlAs region above the second AlAs region.