Gain coupled AlGaInAs/GaInAs DFB-lasers utilizing gratings by masked implantation enhanced intermixing

Masked implantation enhanced intermixing (MIEI) offers the advantage of a full planar technology for realization of gain coupled (GC)-DFB-lasers with the potential of a simplified laser/waveguide coupling with a reduced number of process steps for integration. The high implantation contrast reached in the AlGaInAs/GaInAs material system offers the capability of defining DFB-gratings by implantation. The process is based on the precise control of MBE grown Al/GaInAs/GaInAs-MQW´s in terms of high control of uniformity (lateral and vertical) as well as on the overgrowth of implanted regions necessary to accomplish a complete laser structure. We demonstrate GC-DFB-laser operation based on MIEI gratings and in addition the variation of GC-DFB-laser modulation speed by suitable design of the MIEI grating period. Additionally, cleaning of Al-containing surfaces by H* radical treatment for native oxide removal and successful MBE regrowth on AlGaInAs surfaces as a basic requirement for overgrowth of implanted regions is demonstrated