In this work, we have investigated AlGaAs vertical-cavity surface-emitting lasers (VCSELs) with the aim of achieving high-output power while maintaining single mode operating condition. This effort is motivated by emerging applications such as quantum gyroscopes, where these characteristics are necessary for optical atomic pumping. Our analysis began by assessing device self-heating through thermal modeling simulations, carried out with an in-house 3D finite element method solver. The investigation covered both compact and elongated oxide aperture geometries, revealing significant differences in their thermal dissipation characteristics. To investigate the optical behavior of the device we employed our in-house optical mode solver VELMS, incorporating the temperature profile generated by self-heating effect as the corresponding refractive index variation throughout the device structure.