Impact of Selective DBR Surface Etching on the Performance of 1300 and 1500-nm Wafer-Fused VCSELs

We study the impact of cavity photon lifetime tuning on the performance of long-wavelength wafer-fused vertical-cavity surface-emitting lasers (VCSELs). By selectively etching the topmost layer of the exposed distributed Bragg reflector (DBR) we both reduce the cavity photon lifetime and increase the output-coupling DBR loss rate, thus trading increased bandwidth, output power, and slope efficiency for a small increase in threshold current. Our technique allows us to either individually or on an industrial wafer-scale adjust and tune the performance of post-processed VCSELs to optimize the performance for specific applications or to help correct for processing non-uniformities. Using our etching technique we also extract the internal quantum efficiency of 1300 and 1500-nm VCSELs.