Parasitics and design considerations on oxide-implant VCSELs

Vertical-cavity surface-emitting lasers (VCSELs) are the enabling technology for low-cost high bit rate communication systems. However, the device parasitics typically limit the high-speed performance. In this letter, the modulation responses of oxide-confined and oxide-implant VCSELs are compared. Both of the configurations were fabricated side by side on the same sample and were thoroughly examined. In oxide-implant VCSELs, the low frequency parasitic rolloff is removed by additional implantation. A VCSEL radiatively coupled model is shown to match the experimental data very well without any fitting parameters. This model can be used to design the device geometry and eliminate the parasitic limitation on high-speed performance.