Mode Behavior of VCSELs With Impurity-Induced Disordering

This letter explores the modal behavior of oxide-confined vertical-cavity surface-emitting lasers (VCSELs) with varying emission apertures defined by impurity-induced disordering (IID) via closed ampoule zinc diffusion. A 1-D plane wave propagation method is used to calculate the mirror loss as a function of IID strength and depth. The devices are fabricated with masked areas ranging from approximately 70%-110% of the oxide aperture defining an unmodified emission aperture designed to overlap mainly with the fundamental mode. An analysis of the transverse mode lasing characteristics and mode-dependent thermal characteristics demonstrates a decrease in thermal performance associated with the increasing overlap between the IID ring and supported optical modes of the VCSEL cavity. A single-mode output power of 1.6 mW with over 30 dBm side-mode suppression ration is achieved from a 3 μm device with an IID-defined output aperture of approximately 1.3 μm. The optimal IID emission aperture to oxide aperture ratio for maximizing the single-fundamental-mode output power is experimentally measured.