Local normal mode analysis index-guided AlGaAs lasers with mode filter

The mode filtering properties of index-guided lasers containing a lateral mode filter section are investigated using the beam propagation method combined with a lateral local normal mode decomposition. These structures are shown to have higher kink currents than filterless devices. Furthermore, the choice of the filter length is observed to be a tradeoff between low thresholds (short filters) and suitable far fields at the filter side (long filters).