Thermal impedance of VCSELs with AlO/sub x/-GaAs DBRs

The authors have measured the thermal impedance of vertical-cavity surface-emitting lasers (VCSELs) with oxide/GaAs DBRs and shown that it is comparable to that of VCSELs with all-semiconductor DBRs. A VCSEL with an 8-μm oxide aperture shows a thermal impedance of 2.8/spl deg/C/mW. By varying the aperture size, the thermal conductance of the material below the active area is 0.255 W/cm/spl deg/C. These results demonstrate that the oxide is not a major barrier to heat transport out of the active region.