Theoretical optimization of transverse waveguiding in oxide-confined VCSELs with internal photonic crystals

We systematically investigate transverse optical modes in oxide-confined vertical-cavity surface-emitting lasers (VCSELs) with photonic crystal (PC) structures embedded within the cavity of the VCSEL. We consider the interplay between the effective refractive index step of the oxide and the semiconductor and the oxide aperture size. The PC lattice period a, the diameter of the holes d, and the number of lattice periods around the central defect are considered. We evaluate confinement factors for the various transverse modes and consider their spatial extent in the transverse plane which we relate to the output power. Results suggest that the power of the single-mode photonic crystal vertical-cavity surface-emitting lasers (PC-VCSELs) is limited by the smaller radius of the fundamental mode of the PC-VCSEL compared to the VCSEL with no PC. We discuss various designs aimed to optimize power into the single-fundamental mode and to discriminate from power going into other modes. (C) 2009 Optical Society of America