Noise properties of index-guided vertical-cavity surface-emitting lasers

A numerical study of the noise characteristics of index-guided vertical-cavity surface-emitting lasers (VCSELs) is presented under single- and two-mode operation by considering the effects of spatial hole-burning and carrier diffusion on the intensity and frequency noise. In the case of single-mode operation, VCSEL noise properties are similar to those of edge-emitting lasers except for a diffusion-induced enhancement of the mode power. In the case of two-mode operation, VCSELs exhibit low-frequency enhancement of the intensity noise because of mode partition. The magnitude and the nature of the enhancement depend on the spatial profiles of the transverse modes supported by the VCSEL. By a proper design of the contact shape and size, it is possible to reduce the mode-partition noise in VCSELs.