We analyze the transverse profiles of oxide-confined vertical-cavity laser
diodes as a function of aperture size. For small apertures we demonstrate t
hat thermal lensing can be the dominant effect in determining the transvers
e resonator properties. me also analyze pattern formation in lasers with la
rge apertures where we observe the appearance of tilted waves. (C) 1999 Opt
ical Society of America [S0740-3224(99)00611-6].