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 optimize the linewidth enhancement factor for use in self
mixing applications.