ABSTRACT
High-performance visible-wavelength vertical-cavity surface-emitting lasers (VCSELs) in the wavelength region near 650 nm are needed for emerging technologies such as highdensity optical storage systems, high-definition laser printing and especially optical commu nication systems based on plastic optical fibers, for which absorption losses have a minimum at 650 nm. Furthermore, visible VCSELs can be used for low cost applications e. g. light bar riers or distance measurements. In this case the eye sensitivity and the eye safety demand wavelengths λ of 650 nm or less, output powers of maximum 1 mW and operation tempera tures up to 50°C. While high-performance near-IR (In)GaAs/AlGaAs VCSELs are commer cially available, there are only a few publications concerning AlGalnP-based VCSELs with wavelengths near 650 nm. In 1996, K. D. Choquette et al. [1] reported a continuous-wave (cw) output power of 0.28 mW for 652 nm, but there was no breakthrough in the following years. In 2000, they reported a maximum output power of 0.4 mW at 650 nm [2]. Most of the other groups investigated VCSELs with longer wavelengths, of, e. g., 667 nm with an output power of 2.0 mW [3] or even longer wavelengths up to 690 nm [4]. However, the maximum output is known to decrease drastically with decreasing wavelength.
