Effects of layer thickness variations on vertical-cavity surface-emitting DBR semiconductor lasers

Abstract

A theoretical analysis of the influence of layer thickness variation in vertical-cavity surface-emitting lasers with distributed Bragg reflectors (DBRs) on lasing wavelength is presented. It is shown that changing the active region length of one of the layers in the DBR mirror by only one unit cell (0.56 nm) is sufficient to produce shifts in the lasing wavelength up to 0.12 nm (for an AlGaAs laser). This could limit the precision with which a desired wavelength, its reproducibility, and its uniformity across a large wafer can be obtained. Possible influences on the linewidth of broad area devices are also discussed.