Ridge-waveguide InAs/GaAs lasers

We report on the reduction of current spreading of InAs/GaAs lasers by using ridge-waveguide geometry. For the investigation of current spreading, lasers with various ridge widths 5, 10, 20 and 50 /spl mu/m are prepared. The laser properties are experimentally studied by the light output versus current characteristics (L-I) and near field patterns (NFP). Threshold current densities (J/sub th/) as a function of ridge width are compared to oxide-stripe geometry lasers with the same material structure. Finally, lasers with ridge-waveguide geometry show a reduction of total J/sub th/ for all ridge widths. Furthermore, the fundamental zero-order mode TEM/sub 00/ is achieved for 10 /spl mu/m ridge width.