High Slope Efficiency Bipolar Cascade 905nm Vertical Cavity Surface Emitting Laser

High-performance two-stage bipolar cascade 905nm vertical cavity surface emitting lasers (VCSELs) are designed and fabricated. Three different designs are investigated to compare the electrical and optical properties. Experimental results show that the current spreading and thermal problems are important factors affecting the device performance. The device with two oxide apertures accompanied with a 1.5λ-long active region spacing exhibits a very high slope efficiency of 2.27W/A and a relatively high power conversion efficiency of 52.4%. Such high-performance bipolar cascade VCSELs with 905nm are very important for LiDAR and automotive applications.