Improved output performance of high-power VCSELs

The intention of this paper is to report on state-of-the-art high-power ver tical-cavity surface-emitting laser diodes (VCSELs), single devices as well as two-dimensional (2-D) arrays. Both approaches are studied in terms of e lectrooptical characteristics, beam performance, and scaling behavior. The maximum continuous wave (CW) output power at room temperature of large-area bottom-emitting devices with active diameters up to 320 mum is as high as 0.89 W, which is to our knowledge the highest value reported for a single d evice. Measurements under pulsed conditions show more than 10-W optical pea k output power. Also, the CW performance of 2-D arrays has been increased f rom 0.56 W for 23 elements to 1.55 W for 19 elements due to significantly i mproved heat sinking. The extracted power densities spatially averaged over the area close to the honeycomb-like array arrangement raised from 0.33 kW /cm(2) to 1.25 kW/cm(2). Lifetime measurements have proven acceptable relia bility for over 10 000 h at a degradation rate of less than 1 % per 1000 h. The emission wavelength of bottom-emitting devices is restricted to about 900 nm or higher due to fundamental absorption in the GaAs substrate. Windo wing of the substrate has been studied to allow for shorter wavelength emis sion.