A vertical cavity surface emitting laser (VCSEL) optimized for use in self mixing applications. The VCSEL generally includes a bottom distributed Bragg reflector (DBR) mirror formed on a substrate. An active region is formed on the bottom mirror. A top DBR mirror is formed on the active region. A trench is formed in the at least the top mirror. An aperture is oxidized into the VCSEL. At least one of the bottom DBR mirror, the top DBR mirror, the metal contacts, the trench, and/or the aperture is optimized to make the VCSEL more thermally sensitive to changes in current through the VCSEL.